Gender inequality and utilization of ART: an international cross-sectional and longitudinal analysis.

STUDY QUESTION: What is the association between a country's level of gender equality and access to ART, as measured through ART utilization? SUMMARY ANSWER: ART utilization is associated with a country's level of gender equality even after controlling for the level of development. WHAT IS KNOWN ALREADY: Although gender equality is recognized as an important determinant of population health, its association with fertility care, a highly gendered condition, has not been explored. STUDY DESIGN, SIZE, DURATION: A longitudinal cross-national analysis of ART utilization in 69 countries during 2002-2014 was carried out. PARTICPANTS/MATERIALS, SETTING, METHODS: The Gender Inequality Index (GII), Human Development Index (HDI), and their component indicators were modelled against ART utilization using univariate regression models as well as mixed-effects regression methods (adjusted for country, time, and economic/human development) with multiple imputation to account for missing data. MAIN RESULTS AND THE ROLE OF CHANCE: ART utilization is associated with the GII. In an HDI-adjusted analysis, a one standard deviation decrease in the GII (towards greater equality) is associated with a 59% increase in ART utilization. Gross national income per capita, the maternal mortality ratio, and female parliamentary representation were the index components most predictive of ART utilization. LIMITATIONS, REASONS FOR CAUTION: Only ART was used rather than all infertility treatments (including less costly and non-invasive treatments such as ovulation induction). This was a country-level analysis and the results cannot be generalized to smaller groups. Not all modelled variables were available for each country across 2002-2014. WIDER IMPLICATIONS OF THE FINDINGS: Access to fertility care is central to women's sexual and reproductive health, to women's rights, and to human rights. As gender equality improves, so does access to ART. This relation is likely to be reinforcing and bi-directional, with progress towards global, equitable access to fertility care also improving women's status and participation in societies. STUDY FUNDING/COMPETING INTEREST(S): External funding was not provided for this study. G.D.A. declares consulting fees from Labcorp and CooperSurgical. G.D.A. is the founder and CEO of Advanced Reproductive Care, Inc., as well as the Chair of the International Committee for Monitoring Assisted Reproductive Technologies (ICMART) and the World Endometriosis Research Foundation, both of which are unpaid roles. G.M.C. is an ICMART Board Representative, which is an unpaid role, and no payments are received from ICMART to UNSW, Sydney, or to G.M.C. to undertake this study. O.F., S.D., F.Z.-H., and E.K. report no conflicts of interest. TRIAL REGISTRATION NUMBER: N/A.

Estimating the impact of bias in causal epidemiological studies: the case of health outcomes following assisted reproduction.

Researchers interested in causal questions must deal with two sources of error: random error (random deviation from the true mean value of a distribution), and bias (systematic deviance from the true mean value due to extraneous factors). For some causal questions, randomization is not feasible, and observational studies are necessary. Bias poses a substantial threat to the validity of observational research and can have important consequences for health policy developed from the findings. The current piece describes bias and its sources, outlines proposed methods to estimate its impacts in an observational study, and demonstrates how these methods may be used to inform debate on the causal relationship between medically assisted reproduction (MAR) and health outcomes, using cancer as an example. In doing so, we aim to enlighten researchers who work with observational data, especially regarding the health effects of MAR and infertility, on the pitfalls of bias, and how to address them. We hope that, in combination with the provided example, we can convince readers that estimating the impact of bias in causal epidemiologic research is not only important but necessary to inform the development of robust health policy and clinical practice recommendations.

Risk for Congenital Anomalies in Children Conceived With Medically Assisted Fertility Treatment : A Population-Based Cohort Study.

BACKGROUND: More than 2 million children are conceived annually using assisted reproductive technologies (ARTs), with a similar number conceived using ovulation induction and intrauterine insemination (OI/IUI). Previous studies suggest that ART-conceived children are at increased risk for congenital anomalies (CAs). However, the role of underlying infertility in this risk remains unclear, and ART clinical and laboratory practices have changed drastically over time, particularly there has been an increase in intracytoplasmic sperm injection (ICSI) and cryopreservation. OBJECTIVE: To investigate the role of underlying infertility and fertility treatment on CA risks in the first 2 years of life. DESIGN: Propensity score-weighted population-based cohort study. SETTING: New South Wales, Australia. PARTICIPANTS: 851 984 infants (828 099 singletons and 23 885 plural children) delivered between 2009 and 2017. MEASUREMENTS: Adjusted risk difference (aRD) in CAs of infants conceived through fertility treatment compared with 2 naturally conceived (NC) control groups-those with and without a parental history of infertility (NC-infertile and NC-fertile). RESULTS: The overall incidence of CAs was 459 per 10 000 singleton births and 757 per 10 000 plural births. Compared with NC-fertile singleton control infants (n = 747 018), ART-conceived singleton infants (n = 31 256) had an elevated risk for major genitourinary abnormalities (aRD, 19.0 cases per 10 000 births [95% CI, 2.3 to 35.6]); the risk remained unchanged (aRD, 22 cases per 10 000 births [CI, 4.6 to 39.4]) when compared with NC-infertile singleton control infants (n = 36 251) (that is, after accounting for parental infertility), indicating that ART remained an independent risk. After accounting for parental infertility, ICSI in couples without male infertility was associated with an increased risk for major genitourinary abnormalities (aRD, 47.8 cases per 10 000 singleton births [CI, 12.6 to 83.1]). There was some suggestion of increased risk for CAs after fresh embryo transfer, although estimates were imprecise and inconsistent. There were no increased risks for CAs among OI/IUI-conceived infants (n = 13 574). LIMITATIONS: This study measured the risk for CAs only in those children who were born at or after 20 weeks' gestation. Observational study design precludes causal inference. Many estimates were imprecise. CONCLUSION: Patients should be counseled on the small increased risk for genitourinary abnormalities after ART, particularly after ICSI, which should be avoided in couples without problems of male infertility. PRIMARY FUNDING SOURCE: Australian National Health and Medical Research Council.

Does a public online IVF prediction tool help set patient expectations? A mixed methods evaluation study.

STUDY QUESTION: Does a public online IVF success prediction calculator based on real-world data help set patient expectations? SUMMARY ANSWER: The YourIVFSuccess Estimator aided consumer expectations of IVF success: one quarter (24%) of participants were unsure of their estimated IVF success before using the tool; one half changed their prediction of success after using the tool and one quarter (26%) had their expectations of IVF success confirmed. WHAT IS KNOWN ALREADY: Several web-based IVF prediction tools exist worldwide but have not been evaluated for their impact on patient expectations, nor for patient perceptions of usefulness and trustworthiness. STUDY DESIGN, SIZE, DURATION: This is a pre-post evaluation of a convenience sample of 780 online users of the Australian YourIVFSuccess Estimatorhttps://yourivfsuccess.com.au/ between 1 July and 31 November 2021. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants were eligible if they were over 18 years of age, Australian residents, and considering IVF for themselves or their partner. Participants filled in online surveys before and after using the YourIVFSuccess Estimator. MAIN RESULTS AND THE ROLE OF CHANCE: The response rate of participants who completed both surveys and the YourIVFSuccess Estimator was 56% (n = 439). The YourIVFSuccess Estimator aided consumer expectations of IVF success: one quarter (24%) of participants were unsure of their estimated IVF success before using the tool; one half changed their prediction of success after using the tool (20% increased, 30% decreased), bringing their predictions in line with the YourIVFSuccess Estimator, and one quarter (26%) had their IVF success expectations confirmed. One in five participants claimed they would change the timing of IVF treatment. The majority of participants found the tool to be at least moderately trustworthy (91%), applicable (82%), and helpful (80%), and would recommend it to others (60%). The main reasons given for the positive responses were that the tool is independent (government funded, academic) and based on real-world data. Those who did not find it applicable or helpful were more likely to have had a worse-than-expected prediction, or to have experienced non-medical infertility (e.g. single women, LGBTQIA+), noting that at the time of evaluation the Estimator did not accommodate these patient groups. LIMITATIONS, REASONS FOR CAUTION: Those who dropped out between the pre- and post-surveys tended to have a lower education status or have been born outside of Australia or New Zealand, therefore there may be issues with generalizability. WIDER IMPLICATIONS OF THE FINDINGS: With consumers demanding increasing levels of transparency and participation in decisions around their medical care, public-facing IVF predictor tools based on real-world data are useful for aligning expectations about IVF success rates. Given differences in patient characteristics and IVF practices internationally, national data sources should be used to inform country-specific IVF prediction tools. STUDY FUNDING/COMPETING INTEREST(S): The YourIVFSuccess website and evaluation of the YourIVFSuccess Estimator are supported by the Medical Research Future Fund (MRFF) Emerging Priorities and Consumer Driven Research initiative: EPCD000007. BKB, ND, and OF have no conflicts to declare. DM holds a clinical role at Virtus Health. His role did not influence the analysis plan or interpretation of results in this study. GMC is an employee of the UNSW Sydney, and Director of the UNSW NPESU. UNSW receives research funding on behalf of Prof Chambers from the MRFF to develop and manage the Your IVF Success website. Grant ID: MRFF Emerging Priorities and Consumer Driven Research initiative: EPCD000007. TRIAL REGISTRATION NUMBER: N/A.

Evaluating the Prevention Benefit of HCV Treatment: Modeling the SToP-C Treatment as Prevention Study in Prisons.

BACKGROUND AND AIMS: Between 2014 and 2019, the SToP-C trial observed a halving in HCV incidence in four Australian prisons following scale-up of direct-acting antiviral (DAA) therapy. However, the contribution of HCV treatment to this decline is unclear because the study did not have a control group. We used modeling to consider this question. APPROACH AND RESULTS: We parameterized and calibrated a dynamic model of HCV transmission in prisons to data from each SToP-C prison on incarceration dynamics, injecting drug use, HCV prevalence trends among prison entrants, baseline HCV incidence before treatment scale-up, and subsequent HCV treatment scale-up. The model projected the decrease in HCV incidence resulting from increases in HCV treatment and other effects. We assessed whether the model agreed better with observed reductions in HCV incidence overall and by prison if we included HCV treatment scale-up, and its prevention benefits, or did not. The model estimated how much of the observed decrease in HCV incidence was attributable to HCV treatment in prison. The model projected a decrease in HCV incidence of 48.5% (95% uncertainty interval [UI], 41.9-54.1) following treatment scale-up across the four prisons, agreeing with the observed HCV incidence decrease (47.6%; 95% CI, 23.4-64.2) from the SToP-C trial. Without any in-prison HCV treatment, the model indicated that incidence would have decreased by 7.2% (95% UI, -0.3 to 13.6). This suggests that 85.1% (95% UI, 72.6-100.6) of the observed halving in incidence was from HCV treatment scale-up, with the remainder from observed decreases in HCV prevalence among prison entrants (14.9%; 95% UI, -0.6 to 27.4). CONCLUSIONS: Our results demonstrate the prevention benefits of scaling up HCV treatment in prison settings. Prison-based DAA scale-up should be an important component of HCV elimination strategies.

Residential proximity to a fertility clinic is independently associated with likelihood of women having ART and IUI treatment.

STUDY QUESTION: Is geographic proximity to a fertility clinic associated with the likelihood of women of reproductive age undertaking different forms of medically assisted fertility treatment? SUMMARY ANSWER: After adjusting for socioeconomic status (SES) and other confounders including a proxy for the need for infertility treatment, women who lived within 15 km of a fertility clinic were 21% more likely to undergo ART treatment and 68% more likely to undergo IUI treatment than those who lived further than 60 km away. WHAT IS KNOWN ALREADY: In most countries, patients living outside of metropolitan areas are more likely to be more socio-economically disadvantaged and to have less equitable access to healthcare. However, how a woman's residential proximity to fertility clinics predicts utilization of high-cost/high-technology treatment (ART) and low-cost/low-technology treatment (IUI) is limited, and whether socio-economic disadvantage explains much of the hypothesized lower utilization is unknown. Australia's universal insurance scheme provides supportive reimbursement for almost all ART and IUI treatment regardless of age or number of cycles, providing a unique setting to investigate disparities in access to infertility treatment. STUDY DESIGN, SIZE, DURATION: National population-based observation study of ART and IUI treatment utilization by women across socio-economic gradients and Australian residential locations between August 2015 and December 2017. PARTICIPANTS/MATERIALS, SETTING, METHODS: Universal insurance claims information on female patients who underwent ART or IUI were provided by Services Australia, comprising 67 670 female patients who accessed 162 795 ART treatments, and 10 211 female patients who accessed 19 615 IUI treatments over a 29-month period. Incidence rates by SES and proximity to fertility clinics were calculated to describe the number of women undergoing at least one ART or IUI treatment cycle per 1000 women of reproductive age (25-44). Treatment frequencies were calculated to describe the average number of ART or IUI treatment cycles per woman of reproductive age who had undergone at least one ART or IUI treatment during the study period. Poisson regression analyses were used to estimate the independent effect on accessibility to infertility treatment by geographic proximity (based on small area locations) to the closest fertility clinic after adjusting for SES, childbearing delay, remoteness area, and marital status. MAIN RESULTS AND THE ROLE OF CHANCE: On average, 19.1 women per 1000 women of reproductive age underwent at least one fresh or frozen ART cycle, with an average 2.3 ART cycles each, while 3.0 women per 1000 women of reproductive age received at least one IUI cycle, with an average of 1.6 IUI cycles each. After adjusting for SES and other confounders including a proxy for the need for infertility treatment, women who lived within 15 km of a fertility clinic were 21% more likely to undergo ART treatment and 68% more likely to undergo IUI than those who lived over 60 km away. Regardless of geographic location, there was a steady and independent gradient in access to ART treatment based on increasing SES, with women residing in the most advantaged residential quartile having a 37% higher rate of receiving ART treatment compared to those in the most disadvantaged quartile. The negative effect of social disadvantage on ART use became more pronounced as distance from a fertility clinic grew, indicating that the barriers to access to ART care caused by distance were further compounded by the level of socioeconomic advantage of the women's residential location. In contrast, socioeconomic status did not modify the likelihood of using IUI over and above the distance from a fertility clinic. In relation to IUI treatment, differences in utilization by SES disappeared after adjusting for geographic proximity to a fertility clinic, childbearing delay, remoteness area, and marital status. LIMITATIONS, REASONS FOR CAUTION: Information is aggregated by small geographic areas and it therefore may not reflect individual characteristics. Australia provides partial but comparably supportive reimbursement for both ART and IUI through its universal healthcare system and thus the results may not be fully generalizable to other settings. WIDER IMPLICATIONS OF THE FINDINGS: Residential proximity to a fertility clinic is a persistent barrier to accessing ART and IUI treatment, regardless of SES, even in countries characterized by supportive public funding, such as Australia. SES is less of a barrier to accessing IUI than ART, presumably driven by the lower cost and fewer clinic visits required with IUI treatment. Safe and effective fertility treatment should be available to all women regardless of where they live. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the Australian National University Research scholarship and by the Higher Degree Research Fee Merit Scholarship. The authors have no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

Population-wide contribution of medically assisted reproductive technologies to overall births in Australia: temporal trends and parental characteristics.

STUDY QUESTION: In a country with supportive funding for medically assisted reproduction (MAR) technologies, what is the proportion of MAR births over-time? SUMMARY ANSWER: In 2017, 6.7% of births were conceived by MAR (4.8% ART and 1.9% ovulation induction (OI)/IUI) with a 55% increase in ART births and a stable contribution from OI/IUI births over the past decade. WHAT IS KNOWN ALREADY: There is considerable global variation in utilization rates of ART despite a similar infertility prevalence worldwide. While the overall contribution of ART to national births is known in many countries because of ART registries, very little is known about the contribution of OI/IUI treatment or the socio-demographic characteristics of the parents. Australia provides supportive public funding for all forms of MAR with no restrictions based on male or female age, and thus provides a unique setting to investigate the contribution of MAR to national births as well as the socio-demographic characteristics of parents across the different types of MAR births. STUDY DESIGN, SIZE, DURATION: This is a novel population-based birth cohort study of 898 084 births using linked ART registry data and administrative data including birth registrations, medical services, pharmaceuticals, hospital admissions and deaths. Birth (a live or still birth of at least one baby of ≥400 g birthweight or ≥20 weeks' gestation) was the unit of analysis in this study. Multiple births were considered as one birth in our analysis. PARTICIPANTS/MATERIALS, SETTING, METHODS: This study included a total of 898 084 births (606 488 mothers) in New South Wales and the Australian Capital Territory, Australia 2009-2017. We calculated the prevalence of all categories of MAR-conceived births over the study period. Generalized estimating equations were used to examine the association between parental characteristics (parent's age, parity, socio-economic status, maternal country of birth, remoteness of mother's dwelling, pre-existing medical conditions, smoking, etc.) and ART and OI/IUI births relative to naturally conceived births. MAIN RESULTS AND THE ROLE OF CHANCE: The proportion of MAR births increased from 5.1% of all births in 2009 to 6.7% in 2017, representing a 30% increase over the decade. The proportion of OI/IUI births remained stable at around 2% of all births, representing 32% of all MAR births. Over the study period, ART births conceived by frozen embryo-transfer increased nearly 3-fold. OI/IUI births conceived using clomiphene citrate decreased by 39%, while OI/IUI births conceived using letrozole increased 56-fold. Overall, there was a 55% increase over the study period in the number of ART-conceived births, rising to 56% of births to mothers aged 40 years and older. In 2017, almost one in six births (17.6%) to mothers aged 40 years and over were conceived using ART treatment. Conversely, the proportion of OI/IUI births was similar across different mother's age groups and remained stable over the study period. ART children, but not OI/IUI children, were more likely to have parents who were socio-economically advantaged compared to naturally conceived children. For example, compared to naturally conceived births, ART births were 16% less likely to be born to mothers who live in the disadvantaged neighbourhoods after accounting for other covariates (adjusted relative risk (aRR): 0.84 [95% CI: 0.81-0.88]). ART- or OI/IUI-conceived children were 25% less likely to be born to immigrant mothers than births after natural conception (aRR: 0.75 [0.74-0.77]). LIMITATIONS, REASONS FOR CAUTION: The social inequalities that we observed between the parents of children born using ART and naturally conceived children may not directly reflect disparities in accessing fertility care for individuals seeking treatment. WIDER IMPLICATIONS OF THE FINDINGS: With the ubiquitous decline in fertility rates around the world and the increasing trend to delay childbearing, this population-based study enhances our understanding of the contribution of different types of MARs to population profiles among births in high-income countries. The parental socio-demographic characteristics of MAR-conceived children differ significantly from naturally conceived children and this highlights the importance of accounting for such differences in studies investigating the health and development of MAR-conceived children. STUDY FUNDING/COMPETING INTEREST(S): This study was funded through Australian National Health and Medical Research Council (NHMRC) grant: APP1127437. G.M.C. is an employee of The University of New South Wales (UNSW) and Director of the National Perinatal Epidemiology and Statistics Unit (NPESU), UNSW. The NPESU manages the Australian and New Zealand Assisted Reproduction Database with funding support from the Fertility Society of Australia and New Zealand. C.V. is an employee of The University of New South Wales (UNSW), Director of Clinical Research of IVFAustralia, Member of the Board of the Fertility Society of Australia and New Zealand, and Member of Research Committee of School of Women's and Children's Health, UNSW. C.V. reports grants from Australian National Health and Medical Research Council (NHMRC), and Merck KGaA. C.V. reports consulting fees, and payment or honoraria for lectures, presentations, speakers, bureaus, manuscript, writing or educational events or attending meeting or travel from Merck, Merck Sparpe & Dohme, Ferring, Gedon-Richter and Besins outside this submitted work. C.V. reported stock or stock options from Virtus Health Limited outside this submitted work. R.J.N. is an employee of The University of Adelaide, and Chair DSMC for natural therapies trial of The University of Hong Kong. R.J.N. reports grants from NHMRC. R.J.N. reports lecture fees and support for attending or travelling for lecture from Merck Serono which is outside this submitted work. L.R.J. is an employee of The UNSW and Foundation Director of the Centre for Big Data Research in Health at UNSW Sydney. L.R.J. reports grants from NHMRC. The other co-authors have no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

Double jeopardy-pregnancy and birth during a catastrophic bushfire event followed by a pandemic lockdown, a natural experiment.

BACKGROUND: From November 2019 to January 2020, eastern Australia experienced the worst bushfires in recorded history. Two months later, Sydney and surrounds were placed into lockdown for six weeks due to the COVID-19 pandemic, followed by ongoing restrictions. Many pregnant women at this time were exposed to both the bushfires and COVID-19 restrictions. OBJECTIVE: To assess the impact of exposure to bushfires and pandemic restrictions on perinatal outcomes. METHODS: The study included 60 054 pregnant women who gave birth between November 2017 and December 2020 in South Sydney. Exposure cohorts were based on conception and birthing dates: 1) bushfire late pregnancy, born before lockdown; 2) bushfires in early-mid pregnancy, born during lockdown or soon after; 3) conceived during bushfires, lockdown in second trimester; 4) conceived after bushfires, pregnancy during restrictions. Exposure cohorts were compared with pregnancies in the matching periods in the two years prior. Associations between exposure cohorts and gestational diabetes, preeclampsia, hypertension, stillbirth, mode of birth, birthweight, preterm birth and small for gestational age were assessed using generalised estimating equations, adjusting for covariates. RESULTS: A decrease in low birth weight was observed for cohort 1 (aOR 0.81, 95%CI 0.69, 0.95). Conversely, cohort 2 showed an increase in low birth weight, and increases in prelabour rupture of membranes, and caesarean sections (aOR 1.18, 95%CI 1.03, 1.37; aOR 1.21, 95%CI 1.07, 1.37; aOR 1.10 (1.02, 1.18) respectively). Cohort 3 showed an increase in unplanned caesarean sections and high birth weight babies (aOR 1.15, 95%CI 1.04, 1.27 and aOR 1.16, 95%CI 1.02, 1.31 respectively), and a decrease in gestational diabetes mellitus was observed for both cohorts 3 and 4. CONCLUSION: Pregnancies exposed to both severe climate events and pandemic disruptions appear to have increased risk of adverse perinatal outcomes beyond only experiencing one event, but further research is needed.

Patterns of psychiatric admission in Australian pregnant and childbearing women.

PURPOSE: The early postnatal period is a time of increased risk for psychiatric admission. However, there is scope to further examine if this increase in risk extends to the entire perinatal period (pregnancy and first postnatal year), and how it compares to admission outside of the perinatal period. METHODS: Data were linked across birth and hospital admission registers from July 2000 to December 2009. The study cohort, consisting of all pregnant and childbearing women with a psychiatric history, was divided into two groups: case women (at least one perinatal principal psychiatric admission in the study period) (38%) and comparison women (no perinatal principal psychiatric admissions) (62%). Outcomes were admission rate and length of stay adjusted for diagnosis, socio-demographic factors and timing of admission. RESULTS: Antenatal and postnatal admissions rates were both higher than non-perinatal admission rates for case women for all diagnoses. There was little evidence that women with perinatal admissions were at an increased risk of admissions at other times. Socially disadvantaged women had significantly fewer and shorter admissions than their respective counterparts. CONCLUSIONS: The entire perinatal period is a time of increased risk for admission across the range of psychiatric disorders, compared to other times in a woman's childbearing years. Reduced admission rate and length of stay for socially disadvantaged women suggest lack of equity of access highlighting the importance of national perinatal mental health policy initiatives inclusive of disadvantaged groups.

International Committee for Monitoring Assisted Reproductive Technologies world report: assisted reproductive technology, 2014†.

STUDY QUESTION: What were the utilization, effectiveness and safety of practices in assisted reproductive technologies (ART) globally in 2014 and what global trends could be observed? SUMMARY ANSWER: The estimated total number of ART cycles conducted in 76 participating countries in 2014 was 1.93 million representing ∼66% of global activity, with 5-year trends including an increase in success rates and proportion of frozen embryo transfer (FET) cycles, improvement in cumulative live birth rates per aspiration, a continued increase in single embryo transfer (SET) and thus a reduction in multiple birth rates, an increase in preimplantation genetic testing and stabilization in the use of intracytoplasmic sperm injection (ICSI). WHAT IS KNOWN ALREADY: ART is widely practiced throughout the world but continues to be characterized by significant disparities in utilization, practice, effectiveness and safety. The International Committee for Monitoring Assisted Reproductive Technologies (ICMART) annual world report series provides an important instrument for tracking trends in ART treatment and for providing clinical and public health data to ART professionals, health authorities, patients and the general public. STUDY DESIGN, SIZE, DURATION: A retrospective, cross-sectional survey on ART procedures performed globally during 2014 was carried out. A new method for calculating ART utilization rates and number of babies born was introduced in this latest ICMART world report. PARTICIPANTS/MATERIALS, SETTING, METHODS: Overall, 76 countries and 2 746 ART centres submitted data through national and regional ART registries on ART cycles performed during 2014 and their treatment and pregnancy outcomes. ART cycles and outcomes are described at a country level, regionally and globally. Aggregate country data are processed and analyzed based on methods developed by ICMART. MAIN RESULTS AND THE ROLE OF CHANCE: A total of 1 629 179 ART cycles were reported for the treatment year 2014. After imputing data for missing values and non-reporting centres in reporting countries, an estimated 1 929 905 cycles resulted in >439 039 babies in reporting countries. From 2010 to 2014, the number of reported non-donor aspirations and FET cycles increased by 37.3% and 67.5%, respectively. The proportion of women aged ≥40 years undergoing non-donor ART increased from 23.2% in 2010 to 27.0% in 2014. ICSI, as a percentage of non-donor aspiration cycles, remained relatively stable at 64.8%. The IVF/ICSI combined delivery rates per fresh aspiration and FET cycle were 19.9% and 24.3%, respectively. In fresh non-donor cycles, SET increased from 30.0% in 2010 to 40.0% in 2014, while the average number of transferred embryos decreased from 1.95 to 1.73-but with wide country variation. The rate of twin deliveries following fresh non-donor transfers continued to decrease, from 20.4% in 2010 to 16.2% in 2014, and the triplet rate decreased from 1.1% to 0.5%. In FET non-donor cycles in 2014, the SET rate was 61.6%, with an average of 1.43 embryos transferred, resulting in twin and triplet rates of 10.1% and 0.2%, respectively. The cumulative delivery rate per aspiration increased from 27.1% in 2010 to 32.1% in 2014. The overall perinatal mortality rate per 1 000 births was 19.4 following fresh IVF/ICSI cycles and 9.5 following FET cycles. Among reporting countries, oocyte donation cycles represented 7.3% of all embryo transfers (89 751 transfer cycles) and resulted in 39 278 babies. LIMITATIONS, REASONS FOR CAUTION: The data presented are dependent on the quality and completeness of data submitted by individual countries to ICMART directly or through regional registries. This report covers approximately two-thirds of world ART activity. China is a major contributor of global cycles missing from this report. Continued efforts to improve the quality and consistency of ART data reported by registries are still needed, including the use of internationally agreed standard definitions (The International Glossary of Infertility and Fertility Care). A new method was introduced in this report to calculate ART utilization and number of babies born following ART; therefore, these results are not directly comparable with previous reports. WIDER IMPLICATIONS OF THE FINDINGS: The ICMART world reports provide the most comprehensive global statistical census and review of ART utilization, effectiveness, safety and quality. While ART treatment effectiveness and safety continue to increase globally, the wide disparities in access to treatment, procedures performed and embryo transfer practices warrant attention by clinicians and policymakers. The new method for estimating ART utilization and number of babies born provided more conservative estimates compared to the previuos method. STUDY FUNDING/COMPETING INTEREST(S): ICMART receives unrestricted grants from Abbott and Ferring Pharmaceuticals. ICMART also acknowledges financial support from the following organizations: American Society for Reproductive Medicine; Asia Pacific Initiative on Reproduction; European Society of Human Reproduction and Embryology; Fertility Society of Australia and New Zealand; Japan Society for Reproductive Medicine; Japan Society of Fertilization and Implantation; Red Latinoamericana de Reproducción Asistida; and the Society for Assisted Reproductive Technology. S.D. reports industry sponsorship for attendance of conference from Ferring, and research grants to support African Network and Registry of ART from Ferring and Merck outside the submitted work. F.Z.-H. reports lectures at organized webinars for Ferring and Merck. O.I. reports honoraria for consulting from Ferring, Merck and ObsEva, as well as honoraria for lectures from Ferring and Merck. G.M.C., J.d.M., M.B., M.S.K. and G.D.A. have nothing to disclose. TRIAL REGISTRATION NUMBER: N/A.

Female age is associated with the optimal number of oocytes to maximize fresh live birth rates: an analysis of 256,643 fresh ART cycles.

RESEARCH QUESTION: What is the optimal number of oocytes retrieved at which maximum live birth rate is observed after fresh autologous assisted reproductive technology (ART) cycles for women of different ages? DESIGN: Retrospective cohort study of all fresh autologous ART aspiration cycles (n = 256,643) undertaken in Australia and New Zealand between 2009 and 2015. Primary outcome measure was live birth rate (LBR) (delivery of at least one liveborn baby at 20 weeks' gestation or over per fresh aspiration cycle). Cycles were grouped according to female age (<30, 30-34, 35-49, 40-44 and ≥45 years) and ovarian response (one to three, four to nine, 10-14, 15-19, 20-25 and ≥25 oocytes). Secondary outcome was incidence of ovarian hyperstimulation syndrome (OHSS) requiring hospitalization. RESULTS: At different oocyte yields, LBR per fresh aspiration cycle peaked and then declined at, depending on female age: <30 years: six to 11 oocytes (LBR 31-34%); 30-34 years: 11-16 oocytes (LBR 29-30%); 35-39 years: nine to 17 oocytes (LBR 21-24%); and 40-44 years: 15-17 oocytes (LBR 11-12%). The incidence of OHSS increased significantly with the number of oocytes retrieved, from 1.2% with 15 oocytes retrieved to 9.3% with 30 or more oocytes retrieved (P < 0.001). CONCLUSION: The optimal number of oocytes at which maximum LBR was observed in a fresh aspiration cycle was highly dependent on age. Because of the observational nature of the results, a cause-effect relationship between the number of oocytes retrieved and LBR should not be assumed; evidence from well-designed randomized control trials is required before clinical advice can be suggested.

Is there an optimal number of oocytes retrieved at which live birth rates or cumulative live birth rates per aspiration are maximized after ART? A systematic review.

The association between the number of oocytes retrieved and fresh live birth rate (LBR) or cumulative LBR (CLBR), and whether an optimal number of oocytes are retrieved when LBR or CLBR are maximized, are highly relevant clinical questions; however published results are conflicting. A systematic review of all eligible studies (n = 16) published until January 2020 on MEDLINE, Embase, Scopus, CINAHL and Web of Science was conducted. Five studies evaluated only LBR from fresh cycles, five studies evaluated only CLBR from stimulated cycles and six evaluated both. A marked difference was observed between the oocyte yields at which LBR and CLBR were reportedly maximized in the individual studies. On the basis of nine studies, the optimal number of oocytes at which fresh LBR seems to be maximized is proposed to be between 12 and 18 oocytes (15 oocytes was the most common suggestion). On the other hand, CLBR continues to increase with the number of oocytes retrieved. This is the first systematic review on the topic, and it suggests that the retrieval of 12-18 oocytes is associated with maximal fresh LBR, whereas a continuing positive association is present between the number of oocytes retrieved and CLBR.

How Much Is a Human Life Worth? A Systematic Review.

OBJECTIVES: To systematically review studies eliciting monetary value of a statistical life (VSL) estimates within, and across, different sectors and other contexts; compare the reported estimates; and critically review the elicitation methods used. METHODS: In June 2019, we searched the following databases to identify methodological and empirical studies: Cochrane Library, Compendex, Embase, Environment Complete, Informit, ProQuest, PubMed, Scopus, and Web of Science. We used the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines for reporting and a modified Consolidated Health Economic Evaluation Reporting Standards checklist to assess the quality of included studies. RESULTS: We identified 1455 studies, of which we included 120 in the systematic review. A stated-preference approach was used in 76 articles, with 51%, 41%, and 8% being contingent valuation studies, discrete-choice experiments, or both, respectively. A revealed-preference approach was used in 43 articles, of which 74% were based on compensating-wage differentials. The human capital approach was used in only 1 article. We assessed most publications (87%) as being of high quality. Estimates for VSL varied substantially by context (sector, developed/developing country, socio-economic status, etc), with the median of midpoint purchasing power parity-adjusted estimates of 2019 US$5.7 million ($6.8 million, $8.7 million, and $5.3 million for health, labor market, and transportation safety sectors, respectively). CONCLUSIONS: The large variation observed in published VSLs depends mainly on the context rather than the method used. We found higher median values for labor markets and developed countries. It is important that health economists and policymakers use context-specific VSL estimates. Methodological innovation and standardization are needed to maximize comparability of VSL estimates within, and across, sectors and methods.

Cumulative live birth rates for women returning to ART treatment for a second ART-conceived child.

STUDY QUESTION: What are the success rates for women returning to ART treatment in the hope of having a second ART-conceived child. SUMMARY ANSWER: The cumulative live birth rate (LBR) for women returning to ART treatment was between 50.5% and 88.1% after six cycles depending on whether women commenced with a previously frozen embryo or a new ovarian stimulation cycle and the assumptions made regarding the success rates for women who dropped-out of treatment. WHAT IS KNOWN ALREADY: Previous studies have reported the cumulative LBR for the first ART-conceived child to inform patients about their chances of success. However, most couples plan to have more than one child to complete their family and, for that reason, patients commonly return to ART treatment after the birth of their first ART-conceived child. To our knowledge, there are no published data to facilitate patient counseling and clinical decision-making regarding the success rates for these patients. STUDY DESIGN, SIZE, DURATION: A population-based cohort study with 35 290 women who commenced autologous (using their own oocytes) ART treatment between January 2009 and December 2013 and achieved their first treatment-dependent live birth from treatment performed during this period. These women were then followed up for a further 2 years of treatment to December 2015, providing a minimum of 2 years and a maximum of 7 years of treatment follow-up. PARTICIPANTS/MATERIALS, SETTING, METHODS: Cycle-specific LBR and cumulative LBR were calculated for up to six complete ART cycles (one ovarian stimulation and all associated transfers). Three cumulative LBR were calculated based on the likelihood of success in women who dropped-out of treatment (conservative, optimal and inverse probability-weighted (IPW)). A multivariable logistic regression model was used to predict the chance of returning to ART treatment for a second ART-conceived child, and a discrete time logistic regression model was used to predict the chance of achieving a second ART-conceived child up to a maximum of six complete cycles. The models were adjusted for patient characteristics and previous and current treatment characteristics. MAIN RESULTS AND THE ROLE OF CHANCE: Among the women who had their first ART-conceived live birth, 15 325 (43%) returned to treatment by December 2015. LBRs were consistently better in women who recommenced treatment with a previously frozen embryo, compared to women who underwent a new ovarian stimulation cycle. After six complete cycles, plus any surplus frozen embryos, the cumulative LBR was between 60.9% (95% CI: 60.0-61.8%) (conservative) and 88.1% (95% CI: 86.7-89.5%) (optimal) [IPW 87.2% (95% CI: 86.2-88.2%)] for women who recommenced treatment with a frozen embryo, compared to between 50.5% (95% CI: 49.0-52.0%) and 69.8% (95% CI: 67.5-72.2%) [IPW 68.1% (95% CI: 67.3-68.9%)] for those who underwent a new ovarian stimulation cycle. The adjusted odds of a second ART-conceived live birth decreased for women ≥35 years, who waited at least 3 years before returning to treatment, or who required a higher number of ovarian stimulation cycles or double embryo transfer to achieve their first child. LIMITATIONS, REASONS FOR CAUTION: Our estimates do not fully account for a number of individual prognostic factors, including duration of infertility, BMI and ovarian reserve. WIDER IMPLICATIONS OF THE FINDINGS: This is the first study to report success rates for women returning to ART treatment to have second ART-conceived child. These age-specific success rates can facilitate individualized counseling for the large number of patients hoping to have a second child using ART treatment. STUDY FUNDING/COMPETING INTEREST(S): No funding was received to undertake this study. R. Paul and O. Fitzgerald have nothing to declare. D. Lieberman reports being a fertility specialist and receiving non-financial support from MSD and Merck outside the submitted work. C. Venetis reports being a fertility specialist and receiving personal fees and non-financial support from MSD, personal fees and non-financial support from Merck Serono and Beisins and non-financial support from Ferring outside the submitted work. G.M. Chambers reports being a paid employee of the University of New South Wales, Sydney (UNSW) and Director of the National Perinatal Epidemiology and Statistics Unit (NPESU), UNSW. The Fertility Society of Australia (FSA) contracts UNSW to prepare the Australian and New Zealand Assisted Reproductive Technology Database (ANZARD) annual report series and benchmarking reports. TRIAL REGISTRATION NUMBER: NA.

International Committee for Monitoring Assisted Reproductive Technologies world report: assisted reproductive technology 2012†.

STUDY QUESTION: What was the utilization, effectiveness and safety of practices in ART globally in 2012 and what global trends could be observed? SUMMARY ANSWER: The total number of ART cycles increased by almost 20% since 2011 and the main trends were an increase in frozen embryo transfers (FET), oocyte donation, preimplantation genetic testing and single embryo transfers (SET), whereas pregnancy and delivery rates (PR, DR) remained stable, and multiple deliveries decreased. WHAT IS KNOWN ALREADY: ART is widely practiced throughout the world, but continues to be characterized by significant disparities in utilization, availability, practice, effectiveness and safety. The International Committee for Monitoring Assisted Reproductive Technologies (ICMART) annual world report provides a major tool for tracking trends in ART treatment for over 25 years and gives important data to ART professionals, public health authorities, patients and the general public. STUDY DESIGN, SIZE, DURATION: A retrospective, cross-sectional survey on the utilization, effectiveness and safety of ART procedures performed globally during 2012 was carried out. PARTICIPANTS/MATERIALS, SETTING, METHODS: Sixty-nine countries and 2600 ART clinics submitted data on ART cycles performed during the year 2012, and their pregnancy outcome, through national and regional ART registries. ART cycles and outcomes are described at country, regional and global levels. Aggregate country data were processed and analyzed based on methods developed by ICMART. MAIN RESULTS AND ROLE OF CHANCE: A total of 1 149 817 ART cycles were reported for the treatment year 2012. After imputing data for missing values and non-reporting clinics in reporting countries, 1 948 898 cycles (an increase of 18.6% from 2011) resulted in >465 286 babies (+17.9%) in reporting countries. China did not report and is not included in this estimate. The best estimate of global utilization including China is ∼2.8 million cycles and 0.9 million babies. From 2011 to 2012, the number of reported aspirations and FET cycles increased by 6.9% and 16.0%, respectively. The proportion of women aged 40 years or older undergoing non-donor ART increased from 24.0% in 2011 to 25.2% in 2012. ICSI, as a percentage of non-donor aspiration cycles, increased from 66.5% in 2011 to 68.9% in 2012. The IVF/ICSI combined delivery rates per fresh aspiration and FET cycles were 19.8% and 22.1%, respectively. In fresh non-donor cycles, SET increased from 31.4% in 2011 to 33.7% in 2012, while the average number of transferred embryos decreased from 1.91 to 1.88, respectively-but with wide country variation. The rates of twin deliveries following fresh non-donor transfers decreased from 19.6% in 2011 to 18.0% in 2012, and the triplet rate decreased from 0.9% to 0.8%. In FET non-donor cycles, SET was 54.8%, with an average of 1.54 embryos transferred and twin and triplet rates of 11.1% and 0.4%, respectively. The cumulative DR per aspiration increased from 28.0% in 2011 to 28.9% in 2012. The overall perinatal mortality rate per 1000 births was 21.4 following fresh IVF/ICSI and 15.9 per 1000 following FET. LIMITATIONS, REASONS FOR CAUTION: The data presented depend on the quality and completeness of data submitted by individual countries to ICMART directly or through regional registries. This report covers approximately two-thirds of` world ART activity, with a major missing country, China. Continued efforts to improve the quality and consistency of reporting ART data by registries are still needed, including the use of internationally agreed standard definitions (International Glossary of Infertility and Fertility Care). WIDER IMPLICATIONS OF THE FINDINGS: The ICMART world reports provide the most comprehensive global statistical census and review of ART utilization, effectiveness, safety and quality. While ART treatment continues to increase globally, the wide disparities in access to treatment, procedures performed and embryo transfer practices warrant attention by clinicians and policy makers. With the increasing practice of SET and of freeze all and resulting increased proportion of FET cycles, it is clear that PR and DR per aspiration in fresh cycles do not give an overall accurate estimation of ART efficiency. It is time to use cumulative live birth rate per aspiration, combining the outcomes of FET cycles with the associated fresh cycle from which the embryos were obtained, and to obtain global consensus on this approach. STUDY FUNDING/COMPETING INTEREST(S): The authors declare no conflict of interest and no specific support from any organizations in relation to this manuscript. ICMART gratefully acknowledges financial support from the following organizations: American Society for Reproductive Medicine; European Society for Human Reproduction and Embryology; Fertility Society of Australia; Japan Society for Reproductive Medicine; Japan Society of Fertilization and Implantation; Red Latinoamericana de Reproduccion Asistida; Society for Assisted Reproductive Technology; Ferring Pharmaceuticals and Abbott (both providing ICMART unrestricted grants unrelated to world reports). TRIAL REGISTRATION NUMBER: NA.

Standardizing definitions and reporting guidelines for the infertility core outcome set: an international consensus development study† ‡.

STUDY QUESTION: Can consensus definitions for the core outcome set for infertility be identified in order to recommend a standardized approach to reporting? SUMMARY ANSWER: Consensus definitions for individual core outcomes, contextual statements and a standardized reporting table have been developed. WHAT IS KNOWN ALREADY: Different definitions exist for individual core outcomes for infertility. This variation increases the opportunities for researchers to engage with selective outcome reporting, which undermines secondary research and compromises clinical practice guideline development. STUDY DESIGN, SIZE, DURATION: Potential definitions were identified by a systematic review of definition development initiatives and clinical practice guidelines and by reviewing Cochrane Gynaecology and Fertility Group guidelines. These definitions were discussed in a face-to-face consensus development meeting, which agreed consensus definitions. A standardized approach to reporting was also developed as part of the process. PARTICIPANTS/MATERIALS, SETTING, METHODS: Healthcare professionals, researchers and people with fertility problems were brought together in an open and transparent process using formal consensus development methods. MAIN RESULTS AND THE ROLE OF CHANCE: Forty-four potential definitions were inventoried across four definition development initiatives, including the Harbin Consensus Conference Workshop Group and International Committee for Monitoring Assisted Reproductive Technologies, 12 clinical practice guidelines and Cochrane Gynaecology and Fertility Group guidelines. Twenty-seven participants, from 11 countries, contributed to the consensus development meeting. Consensus definitions were successfully developed for all core outcomes. Specific recommendations were made to improve reporting. LIMITATIONS, REASONS FOR CAUTION: We used consensus development methods, which have inherent limitations. There was limited representation from low- and middle-income countries. WIDER IMPLICATIONS OF THE FINDINGS: A minimum data set should assist researchers in populating protocols, case report forms and other data collection tools. The generic reporting table should provide clear guidance to researchers and improve the reporting of their results within journal publications and conference presentations. Research funding bodies, the Standard Protocol Items: Recommendations for Interventional Trials statement, and over 80 specialty journals have committed to implementing this core outcome set. STUDY FUNDING/COMPETING INTEREST(S): This research was funded by the Catalyst Fund, Royal Society of New Zealand, Auckland Medical Research Fund and Maurice and Phyllis Paykel Trust. Siladitya Bhattacharya reports being the Editor-in-Chief of Human Reproduction Open and an editor of the Cochrane Gynaecology and Fertility Group. J.L.H.E. reports being the Editor Emeritus of Human Reproduction. R.S.L. reports consultancy fees from Abbvie, Bayer, Ferring, Fractyl, Insud Pharma and Kindex and research sponsorship from Guerbet and Hass Avocado Board. B.W.M. reports consultancy fees from Guerbet, iGenomix, Merck, Merck KGaA and ObsEva. C.N. reports being the Editor-in-Chief of Fertility and Sterility and Section Editor of the Journal of Urology, research sponsorship from Ferring, and a financial interest in NexHand. E.H.Y.N. reports research sponsorship from Merck. A.S. reports consultancy fees from Guerbet. J.W. reports being a statistical editor for the Cochrane Gynaecology and Fertility Group. A.V. reports that he is a Statistical Editor of the Cochrane Gynaecology & Fertility Review Group and of the journal Reproduction. His employing institution has received payment from Human Fertilisation and Embryology Authority for his advice on review of research evidence to inform their 'traffic light' system for infertility treatment 'add-ons'. N.L.V. reports consultancy and conference fees from Ferring, Merck and Merck Sharp and Dohme. The remaining authors declare no competing interests in relation to the work presented. All authors have completed the disclosure form. TRIAL REGISTRATION NUMBER: Core Outcome Measures in Effectiveness Trials Initiative: 1023.

ART utilization: an indicator of access to infertility care.

This commentary outlines the importance of utilizing assisted reproductive technology (ART) as an indicator of access to infertility care and provides a standard way of reporting utilization to facilitate international comparisons. Factors that influence ART utilization as well as underlying inequalities and inequities in access to care are discussed. The relevance of a marker that can inform and evaluate policy initiatives, monitor progress and document change is emphasized.

New Australian birthweight centiles.

OBJECTIVES: To prepare more accurate population-based Australian birthweight centile charts by using the most recent population data available and by excluding pre-term deliveries by obstetric intervention of small for gestational age babies. DESIGN: Population-based retrospective observational study. SETTING: Australian Institute of Health and Welfare National Perinatal Data Collection. PARTICIPANTS: All singleton births in Australia of 23-42 completed weeks' gestation and with spontaneous onset of labour, 2004-2013. Births initiated by obstetric intervention were excluded to minimise the influence of decisions to deliver small for gestational age babies before term. MAIN OUTCOME MEASURES: Birthweight centile curves, by gestational age and sex. RESULTS: Gestational age, birthweight, sex, and labour onset data were available for 2 807 051 singleton live births; onset of labour was spontaneous for 1 582 137 births (56.4%). At pre-term gestational ages, the 10th centile was higher than the corresponding centile in previous Australian birthweight charts based upon all births. CONCLUSION: Current birthweight centile charts probably underestimate the incidence of intra-uterine growth restriction because obstetric interventions for delivering pre-term small for gestational age babies depress the curves at earlier gestational ages. Our curves circumvent this problem by excluding intervention-initiated births; they also incorporate more recent population data. These updated centile curves could facilitate more accurate diagnosis of small for gestational age babies in Australia.

Projecting future utilization of medically assisted fertility treatments.

This study estimates the future utilization of medically assisted fertility treatments in Australia, focusing on assisted reproductive technologies (ARTs), intrauterine insemination (IUI), and ovulation induction. A multistate cohort component population projection model is used to determine future fertility rates from 2016 to 2026 by age and education level. These are combined with information on recent trends in use and success rates to indirectly estimate future age-specific probabilities of fertility treatment utilization. The number of ART cycles is expected to increase by 61 per cent between 2016 and 2026 if treatment success rates remain at 2015 levels, or by 34 per cent if recent improvements in ART success rates continue. The model also predicts that numbers of IUI cycles and ovulation induction cycles will decrease by 17 and 3 per cent, respectively. This research confirms the importance of including both technological improvements and socio-demographic changes when predicting future fertility treatment utilization.

The number of oocytes associated with maximum cumulative live birth rates per aspiration depends on female age: a population study of 221 221 treatment cycles.

STUDY QUESTION: What is the number of oocytes where the maximum cumulative live birth rate per aspiration (CLBR) is observed during ART in women of different ages? SUMMARY ANSWER: The maximum CLBR was observed when around 25 oocytes were retrieved in women between 18-35 years of age, around 9 oocytes in women more than 45 years of age and continued to increase beyond 30 oocytes in women between 36-44 years of age. WHAT IS KNOWN ALREADY: The live birth rate per fresh or frozen/thaw embryo transfer (FET) procedure has traditionally been the main measure of ART success. However, with the introduction of highly efficient embryo cryopreservation methods, CLBR encompassing live delivery outcomes from the fresh and all subsequent FET following a single ovarian stimulation and oocyte collection is increasingly viewed as a more meaningful measure of treatment success. There is evidence suggesting that larger oocyte yields are associated with increased likelihood of cumulative live birth per aspiration. Whether this association is the same across female ages has not yet been properly investigated. STUDY DESIGN, SIZE, DURATION: This is a large retrospective population-based cohort study using data from the Australian and New Zealand Assisted Reproduction Database (ANZARD). ANZARD contains information from all ART treatment cycles carried out in all fertility centres in Australia and New Zealand. Overall, 221 221 autologous oocyte aspiration cycles carried out between January 2009 to December 2015 were included in the analysis. PARTICIPANTS/MATERIALS, SETTING, METHODS: Cumulative live birth per aspiration was defined as at least one liveborn baby at ≥20 weeks gestation resulting from an ART aspiration cycle, including all fresh and FET resulting from the associated ovarian stimulation, until one live birth occurred or all embryos were used. Cycles where no oocytes were retrieved were excluded from analysis as there is no possibility of live birth. Analyses of data were performed using generalized estimating equations to account for the clustered nature of data (multiple cycles undertaken by a woman). Univariate and multivariable regression analysis was performed to identify and adjust for factors known to independently affect cumulative live birth per aspiration. An interaction term between female age and the number of oocytes retrieved was included to assess whether the age of the women was associated with a different optimal number of oocytes to achieve at least one live birth from an aspiration cycle (i.e. the effect-modifying role of female age). The likelihood of cumulative live birth per aspiration was calculated as odds ratios (ORs) with 95% CI. MAIN RESULTS AND THE ROLE OF CHANCE: The median number of oocytes retrieved was 7 (interquartile range, 4-12) and median age of patients was 36 (interquartile range, 33-40). The overall CLBR was 32.2%. The results from the multivariable regression analysis showedthat the number of oocytes retrieved remained a significant predictor (P < 0.001) of cumulative live birth per aspiration after adjusting for female age, parity and cycle count. Compared to the reference group of 10-14 oocytes retrieved, the adjusted odds for cumulative live birth per aspiration increased with the number of oocytes retrieved: 1-3 oocytes, 0.21 (95% CI, 0.20-0.22); 4-9 oocytes, 0.56 (95% CI, 0.55-0.58); 15-19 oocytes, 1.38 (95% CI, 1.34-1.43); 20-24 oocytes, 1.75 (95% CI, 1.67-1.84); and 2.10 (95% CI, 1.96-2.25) with more than 25 oocytes. After stratifying by female age group, the rate of increase in CLBR per additional oocyte retrieved was lower in the older age groups, indicating that higher oocyte yields were more beneficial in younger women. CLBR of patients in the <30 years and 30-34 years age groups appeared to reach a plateau (with only minimal increase in CLBR per additional oocyte retrieved) after retrieval of 25 oocytes at 73% and 72%, respectively, while CLBR of patients in the 35-39 years and 40-44 years age groups continued to increase with higher oocyte yields, reaching 68% and 40%, respectively, when 30 or more oocytes were retrieved. CLBR of patients aged 45 years and above remained consistently below 5%. Findings suggest that the number of oocytes retrieved where CLBR appears to be maximized is around 25 in women between 18-35 years, more than 30 in women between 36-44 years and around 9 in women 45 years and older. However, results for women aged 45 years and older may not be as robust due to the relatively small sample size available in this age group. LIMITATIONS, REASONS FOR CAUTION: As with all large retrospective database studies, there are potential confounders that cannot be accounted for. Despite the current study being based on complete ascertainment of ART cycles across two countries, ovarian stimulation protocols, oocyte quality parameters and a number of important patient characteristics are not collected by ANZARD. Additionally, a small number of cycles were available for women over 45 years yielding more than 15 oocytes, making these estimates unreliable. WIDER IMPLICATIONS OF THE FINDINGS: The results from this study demonstrate that the number of oocytes retrieved where the maximum CLBR is observed during ART is dependent on female age. This provides information for clinicians and patients to understand the modifying effect of age on the number of oocytes retrieved and the likelihood of success with ART. STUDY FUNDING/COMPETING INTEREST(S): No external funding was used for this study. The Fertility Society of Australia funds the National Perinatal Epidemiology and Statistics Unit to manage ANZARD and conduct national reporting of ART in Australia and New Zealand. Associate Professor Georgina Chambers (G.C.) is employed by the University of New South Wales (UNSW) and is director of the National Perinatal Epidemiology and Statistics Unit at UNSW. G.C. was also a paid member of the Australian governments Medicare Benefits Scheme taskforce on assisted reproductive technologies in 2017.