BEYOND: a randomized controlled trial comparing efficacy and safety of individualized follitropin delta dosing in a GnRH agonist versus antagonist protocol during the first ovarian stimulation cycle.

STUDY QUESTION: How does a gonadotrophin-releasing hormone (GnRH) agonist versus a GnRH antagonist protocol affect ovarian response when using an individualized fixed daily dose of follitropin delta for ovarian stimulation? SUMMARY ANSWER: The BEYOND trial data demonstrate thatindividualized fixed-dose follitropin delta is effective when used in a GnRH agonist protocol, compared with a GnRH antagonist protocol, in women with anti-Müllerian hormone (AMH) ≤35 pmol/l and no increased risk of ovarian hyperstimulation syndrome (OHSS). WHAT IS KNOWN ALREADY: The efficacy and safety of an individualized fixed daily dose of follitropin delta (based on body weight and AMH) have been established in randomized controlled trials (RCTs) using a GnRH antagonist protocol. Preliminary study data indicate that individualized follitropin delta is also efficacious in a GnRH agonist protocol (RAINBOW trial, NCT03564509). There are no prospective comparative data using individualized follitropin delta for ovarian stimulation in a GnRH agonist versus a GnRH antagonist protocol. STUDY DESIGN, SIZE, DURATION: This is the first randomized, controlled, open-label, multi-centre trial exploring efficacy and safety of individualized follitropin delta dosing in a GnRH agonist versus a GnRH antagonist protocol in participants undergoing their first ovarian stimulation cycle for IVF/ICSI. A total of 437 participants were randomized centrally and stratified by centre and age. The primary endpoint was the number of oocytes retrieved. Secondary endpoints included ongoing pregnancy rates, adverse drug reactions (including OHSS), live births, and neonatal outcomes. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants (18-40 years; AMH ≤35 pmol/l) were enrolled at specialist reproductive health clinics in Austria, Denmark, Israel, Italy, the Netherlands, Norway, and Switzerland. The mean number of oocytes retrieved was compared between the GnRH agonist and antagonist protocols using a negative binomial regression model with age and AMH at screening as factors. Analyses were based on all randomized subjects, using a multiple imputation method for randomized subjects withdrawing before the start of stimulation. MAIN RESULTS AND THE ROLE OF CHANCE: Of the 437 randomized subjects, 221 were randomized to the GnRH agonist, and 216 were randomized to the GnRH antagonist protocol. The participants had a mean age of 32.3 ± 4.3 years and a mean serum AMH of 16.6 ± 7.8 pmol/l. A total of 202 and 204 participants started ovarian stimulation with follitropin delta in the GnRH agonist and antagonist groups, respectively. The mean number of oocytes retrieved was statistically significantly higher in the agonist group (11.1 ± 5.9) versus the antagonist group (9.6 ± 5.5), with an estimated mean difference of 1.31 oocytes (95% CI: 0.22; 2.40, P = 0.0185). The difference in number of oocytes retrieved was influenced by the patients' age and ovarian reserve, with a greater difference observed in patients aged <35 years and in patients with high ovarian reserve (AMH >15 pmol/l). Both the GnRH agonist and antagonist groups had a similar proportion of cycle cancellations (2.0% [4/202] versus 3.4% [7/204]) and fresh blastocyst transfer cancellations (13.4% [27/202] versus 14.7% [30/204]). The estimated ongoing pregnancy rate per started cycle was numerically higher in the GnRH agonist group (36.9% versus 29.1%; difference: 7.74% [95% CI: -1.49; 16.97, P = 0.1002]). The most commonly reported adverse events (≥1% in either group; headache, OHSS, nausea, pelvic pain, or discomfort and abdominal pain) were similar in both groups. The incidence of early moderate/severe OHSS was low (1.5% for the agonist group versus 2.5% for antagonist groups). Estimated live birth rates per started cycle were 35.8% and 28.7% in the GnRH agonist and antagonist groups, respectively (treatment difference 7.15%; 95% CI: -2.02; 16.31; P = 0.1265). The two treatment groups were comparable with respect to neonatal health data for singletons and twins and for incidence of congenital malformations (2.7% and 3.3% for the GnRH agonist versus antagonist groups, respectively). LIMITATIONS, REASONS FOR CAUTION: All participants had AMH ≤35 pmol/l and were ≤40 years old. Clinicians should remain cautious when using a GnRH agonist protocol in patients with AMH >35 pmol/l (i.e. those with an increased OHSS risk). The incidence of OHSS in the GnRH antagonist group may have been lower if a GnRH agonist trigger had been allowed. Outcomes of transfers with cryopreserved blastocysts were not followed up, therefore the cumulative live birth rates and neonatal outcomes after cryotransfer are unknown. WIDER IMPLICATIONS OF THE FINDINGS: In women with AMH ≤35 pmol/l, an individualized fixed daily dose of follitropin delta resulted in a significantly higher number of oocytes retrieved when used in a GnRH agonist protocol compared with a GnRH antagonist protocol, with no additional safety signals observed and no additional risk of OHSS. Live birth rates following ovarian stimulation with individualized follitropin delta were not statistically different between the GnRH protocols; however, the trial was not powered to assess this endpoint. There were no safety concerns with respect to neonatal health after ovarian stimulation with follitropin delta in either protocol. STUDY FUNDING/COMPETING INTEREST(S): The trial was funded by Ferring Pharmaceuticals. EE, EP, and MS have no competing interests. AP has received research support from Ferring, and Gedeon Richter, and honoraria or consultation fees from Preglem, Novo Nordisk, Ferring, Gedeon Richter, Cryos, Merck A/S. BC has received consulting fees from Ferring and Merck, and his department received fees from Ferring to cover the costs of patient enrolment. MBS has received support to attend meetings and/or travel from Ferring, and was a board member for FertiPROTEKT e.V. until 2023. JS has received honoraria or consultation fees from Ferring and Merck, and support for attending meetings and/or travel from Ferring, Merck, and GoodLife. TS has received support/travel expenses from Ferring for attending a congress meeting, and participated in an advisory board for Merck. YS has received grants/research support from Ferring and support to attend a professional society congress meeting from Merck. RL and PP are employees of Ferring Pharmaceuticals. PP is a BOD member of PharmaBiome and owns stocks of Takeda Pharmaceuticals. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier NCT03809429; EudraCT Number 2017-002783-40. TRIAL REGISTRATION DATE: 7 April 2019. DATE OF FIRST PATIENT'S ENROLMENT: 2 May 2019.

The risk of Type 1 diabetes in children born after ART: a Nordic cohort study from the CoNARTaS group.

STUDY QUESTION: Do children born after ART have a higher risk of developing Type 1 diabetes (DM1) than children conceived without ART? SUMMARY ANSWER: The risk of DM1 was similar for children conceived with and without ART, and there were no clear differences in risk according to method of fertility treatment. WHAT IS KNOWN ALREADY: ART is associated with a higher risk of adverse perinatal outcomes, and the risk depends on the method of ART. The Developmental Origins of Health and Disease theory proposes that prenatal stress can provoke changes in endocrine processes which impact health later in life. STUDY DESIGN SIZE DURATION: A Nordic register-based cohort study was carried out, including all children born in Denmark (birth years 1994-2014), Finland (1990-2014), and Norway (1984-2015). The study included 76 184 liveborn singletons born after ART and 4 403 419 born without ART. Median follow-up was 8.3 and 13.7 years in the ART and non-ART group, respectively. PARTICIPANTS/MATERIALS SETTING METHODS: The cohort, initiated by the Committee of Nordic Assisted Reproductive Technology and Safety (CoNARTaS), was established by linking national registry data from the medical birth registries and national patient registries available in the Nordic countries. We performed multivariable logistic regression analyses for the birth year intervals 1984-1990, 1991-1995, 1996-2000, 2001-2005, 2006-2010, and 2011-2015, while adjusting for year of birth within each interval, sex of the child, parity, maternal age, maternal diabetes, and maternal smoking during pregnancy as potential confounders. MAIN RESULTS AND THE ROLE OF CHANCE: During follow-up, 259 (3.4‰) children born after ART were diagnosed with DM1, while this was the case for 22 209 (5.0‰) born without ART, corresponding to an adjusted odds ratio of 0.98 (95% CI: 0.861.11). Within the different birth year intervals, no significant difference in risk of DM1 between the two groups was found, except for the youngest cohort of children born 2011-2015 where ART was associated with a higher risk of DM1. We found no significant differences in risk of DM1 when comparing children born after IVF versus ICSI or fresh versus frozen embryo transfer, but with only few cases in each group. LIMITATIONS REASONS FOR CAUTION: The main limitation of the study is the relatively short follow-up time. The incidence rate of DM1 peaks during ages 10-14 years, hence a longer follow-up would benefit all analyses and, in particular, the subgroup analyses. WIDER IMPLICATIONS OF THE FINDINGS: Overall, our findings are reassuring especially considering the concomitantly increasing number of children born from ART and the increasing incidence of DM1 globally. STUDY FUNDING/COMPETING INTERESTS: This Nordic registry study has been supported by the Nordic Trial Alliance/NORDFORSK and Rigshospitalets Research Foundation. The funding sources had no role in study design; in the collection, analysis, and interpretation of data; in the writing of the report; and in the decision to submit the article for publication. None of the authors has any conflicts of interest to declare regarding this study. TRIAL REGISTRATION NUMBER: ISRCTN11780826.

Progesterone concentrations on blastocyst transfer day in modified natural cycle frozen embryo transfer cycles.

RESEARCH QUESTION: Are serum progesterone concentrations on the day of modified natural cycle (mNC) frozen blastocyst transfer (FET) without luteal phase support (LPS) associated with clinical pregnancy rate (CPR)? DESIGN: Data were collected between January 2019 and October 2022 as a sub-study of an ongoing randomized controlled trial assessing pregnancy outcomes in mNC-FET. The sub-study included all women (n = 209) randomized to mNC-FET without LPS at the time of data extraction. Participants were aged 18-41 years, had regular menstrual cycles and underwent mNC-FET treatment with single-blastocyst transfer. Associations between the serum progesterone concentration on the day of blastocyst transfer and CPR, pregnancy rate and pregnancy loss rate (PLR) were examined between groups with low and higher progesterone concentrations using the 25th and 10th percentiles as cut-offs. Multivariate logistic regression analyses were performed to adjust for potential confounding factors. RESULTS: Progesterone concentrations on the day of blastocyst transfer in mNC-FET without LPS ranged from 4.9 to 91.8 nmol/l, with the 25th and 10th percentiles at 29.0 nmol/l and 22.5 nmol/l, respectively. Serum progesterone concentrations did not differ between women with or without a clinical pregnancy (mean [SD] 38.5 [14.0] versus 36.8 [12.4] nmol/l; P = 0.350). Furthermore, the CPR, pregancy rate and PLR were similar in women with low or high progesterone concentrations when using the 25th or the 10th progesterone percentile as cut-off. Multivariate regression analyses showed no association between progesterone concentrations and CPR. CONCLUSIONS: No association was found between progesterone concentration on the day of blastocyst transfer and pregnancy outcome in women undergoing mNC-FET without progesterone LPS.

The prevalence of late-follicular phase progesterone elevation and impact on the ongoing pregnancy rate after fresh and frozen blastocyst transfer. Sub-study of an RCT.

The effect of late-follicular phase progesterone elevation (LFPE) during ovarian stimulation on reproductive outcomes in ART treatment remains controversial, but recent studies indicate lower pregnancy rates with rising progesterone levels. This study aims to investigate the prevalence of late-follicular phase progesterone elevation (LFPE) and possible impact on ongoing pregnancy rate after fresh or frozen blastocyst transfer in a sub-study setting of a randomised controlled trial. A total of 288 women were included (n=137 and n=151 in the fresh transfer and freeze-all group, respectively). Among these 11(3.8%) had a progesterone level ≥1.5 ng/ml, and 20(6.9%) had a progesterone level ≥1.2 ng/ml on trigger day. Spline regression analysis showed no significant effect of late follicular phase progesterone levels on ongoing pregnancy. In the multivariate regression analysis (n = 312) only age, but not progesterone level on trigger day was significantly associated with ongoing pregnancy. In conclusion, in a clinical setting with moderate gonadotrophin stimulation and well-defined trigger and fresh transfer cancellation criteria, the prevalence of women with LFPE ≥1.5 ng/ml was low and did not indicate the clinical value of routine measurement of progesterone in the late follicular phase.

Blood pressure and lipid profiles in children born after ART with frozen embryo transfer.

STUDY QUESTION: Are blood pressure (BP) and lipid profiles different between children conceived after ART with frozen embryo transfer (FET), fresh embryo transfer (fresh-ET), and natural conception (NC)? SUMMARY ANSWER: Girls conceived after FET had significantly higher systolic BP and heart rate compared with girls born after fresh-ET; boys conceived after FET had a slightly more favourable lipid profile compared with boys born after fresh-ET and NC. WHAT IS KNOWN ALREADY: Children conceived after ART with FET are more often born large for gestational age (LGA). LGA in general increases the risk of obesity, diabetes, and cardiovascular disease later in life. Studies on mice and humans on the whole ART population have raised concerns about premature vascular ageing and higher BP. The cardiovascular health of children born after FET is scarcely explored and the results are diverging. STUDY DESIGN SIZE DURATION: This study was part of the cohort study 'Health in Childhood following Assisted Reproductive Technology' (HiCART), which included 606 singletons (292 boys) born between December 2009 and December 2013: 200 children were conceived after FET; 203 children were conceived after fresh-ET; and 203 children were conceived naturally and matched for birth year and sex. The study period lasted from January 2019 to September 2021. PARTICIPANTS/MATERIALS SETTING METHODS: The included children were 7-10 years of age at examination and underwent a clinical examination with anthropometric measurements, pubertal staging, and BP measurement. Additionally, a fasting blood sample was collected and analysed for cholesterol, low-density lipoproteins (LDL), high-density lipoproteins (HDL), and triglycerides. Systolic and diastolic BP were converted to standard deviation scores (SDS) using an appropriate reference and accounting for height (SDS) of the child. The three study groups were compared pairwise using a univariate linear regression model. Mean differences were adjusted for confounders using multiple linear regression analyses. MAIN RESULTS AND THE ROLE OF CHANCE: Girls and boys conceived after FET had significantly higher birthweight (SDS) compared with naturally conceived peers (mean difference: girls: 0.35, 95% CI (0.06-0.64), boys: 0.35, 95% CI (0.03-0.68)). Girls conceived after FET had significantly higher systolic BP (SDS) and heart rate compared with girls conceived after fresh-ET (adjusted mean difference: systolic BP (SDS): 0.25 SDS, 95% CI (0.03-0.47), heart rate: 4.53, 95% CI (0.94-8.13)). Regarding lipid profile, no significant differences were found between the three groups of girls. For the boys, no significant differences were found for BP and heart rate. Lipid profiles were more favourable in boys born after FET compared with both boys conceived after fresh-ET and NC. All outcomes were adjusted for parity, maternal BMI at early pregnancy, smoking during pregnancy, educational level, birthweight, breastfeeding, child age at examination, and onset of puberty. LIMITATIONS REASONS FOR CAUTION: The participation rate varied from 18 to 42% in the three groups, and therefore selection bias cannot be excluded. However, extensive non-participant analyses were performed that showed almost no differences in background characteristics between participants and non-participants in the three groups, making selection bias less likely. WIDER IMPLICATIONS OF THE FINDINGS: The higher birthweight in children conceived after FET was associated with increased systolic BP (SDS) and heart rate in girls conceived after FET compared with fresh-ET. This may be an early indicator of compromised long-term cardiovascular health in this group. The study was not powered to investigate these outcomes and further studies are therefore warranted to confirm the findings. STUDY FUNDING/COMPETING INTERESTS: The study was funded by the Novo Nordisk Foundation (grant number: NNF18OC0034092, NFF19OC0054340) and Rigshospitalets Forskningsfond. The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier: NCT03719703.

Endometrial preparation protocols prior to frozen embryo transfer - convenience or safety?

The number of frozen embryo transfer (FET) cycles is increasing rapidly worldwide. Different endometrial preparations for FET result in comparable live birth rates. However, several recent publications have reported higher maternal risks for hypertensive disorders of pregnancy (HDP), pre-eclampsia and postpartum haemorrhage (PPH) in programmed cycles (PC-FET) compared with natural cycles and modified natural cycles with an intact corpus luteum. Nevertheless, PC-FET is frequently used in ovulatory women despite the increased risks for HDP, pre-eclampsia and PPH. Although randomized controlled studies have been suggested, PC-FET raises several methodological problems. Large study populations would be required to investigate the outcomes in question, and the inclusion of ovulatory women, where the intervention may increase the risk of a negative outcome, is ethically troublesome. In the authors' opinion, the existing evidence from large observational studies and systematic reviews is sufficiently strong to recommend an endometrial preparation strategy that aims to maintain or stimulate the corpus luteum to minimize the risk of HDP and pre-eclampsia after FET cycles.

Cardiovascular autonomic nervous function in children conceived by assisted reproductive technology with frozen or fresh embryo transfer.

As a result of epigenetic changes, children conceived by assisted reproduction may be at risk of premature cardiovascular aging with notably increased blood pressures. Their cardiovascular autonomic nervous function is unknown. Therefore, this study investigated the cardiovascular autonomic nervous function in 8-12-yr-old children (51% girls) conceived naturally (n = 33) or by assisted reproduction with frozen (n = 34) or fresh (n = 38) embryo transfer by evaluating heart rate variability, during rest; from provocation maneuvers; and from baroreflex function. Heart rate and blood pressure response to provocation maneuvers and baroreflex function were comparable between children conceived naturally or by assisted reproduction. The mean RR-interval and high-frequency component of heart rate variability were lower in children conceived by assisted reproduction than in children conceived naturally. Children conceived by fresh embryo transfer had ∼17% lower heart rate-corrected standard deviation of normal-to-normal R-R intervals; ∼22% lower heart rate-corrected square root of the mean of the squared difference between successive R-R intervals; and ∼37% higher low-frequency/high-frequency ratio than naturally conceived children. Children conceived by assisted reproduction still had lower heart rate variability and vagal modulation than naturally conceived children after adjustment for confounders. Thus, these results raise the possibility of sympathetic predominance in children conceived by assisted reproduction. Therefore, it is important to reproduce these results in larger and older cohorts as sympathetic predominance relates with cardiovascular and metabolic diseases.NEW & NOTEWORTHY We observed that children conceived by assisted reproductive technology (both frozen and fresh embryo transfer) had lowered heart rate variability during rest as compared with children conceived naturally. During physiological stress maneuvers, however, the cardiovascular autonomic nervous regulation was comparable between children conceived by assisted reproductive technologies and naturally. Our findings highlight the potential that lowered heart rate variability during rest in children conceived by assisted reproductive technologies may precede premature hypertension.

Risk of stroke the year following a delivery after using assisted reproductive technologies.

BACKGROUND: Studies indicate that individuals who deliver after assisted reproductive technologies (ART) may have an increased risk of cardiovascular disease (CVD). A recent large study from the U.S. showed a higher risk of stroke during the first year after delivery. OBJECTIVES: To compare the risk of stroke during the first year after delivery according to the use of ART in the Nordic countries. METHODS: Registry-based cohort study using nationwide data from Denmark (1994-2014), Finland (1990-2014), Norway (1984-2015) and Sweden (1985-2015). Data on ART conception were available from ART quality registries and/or Medical Birth Registries (MBRs). National data on stroke were available from hospital and cause-of-death registries. The risk of stroke during the first year after delivery was estimated with Cox proportional hazard regression, adjusting for age, calendar year of delivery, multiple births, and country. RESULTS: A total of 2,659,272 primiparous individuals had a registered delivery in the MBRs during the study period, and 91,466 (4%) of these gave birth after ART. We observed no overall increased risk of stroke during the first year after delivery among individuals conceiving after ART (adjusted hazard ratio [HR] 1.10, 95% CI 0.77, 1.57). Similarly, there was no convincing evidence that the short-term risk of stroke was higher within 1, 2, 3, or 6 months after delivery, with adjusted HRs ranging between 1.23 and 1.33 and confidence intervals including the null value for all time periods. A secondary analysis also including multiparous individuals (n = 3,335,478) at the start of follow-up yielded similar findings. CONCLUSIONS: We found no evidence of an increased short-term risk of stroke among individuals who delivered after using ART.

Psychosocial wellbeing shortly after allocation to a freeze-all strategy compared with a fresh transfer strategy in women and men: a sub-study of a randomized controlled trial.

STUDY QUESTION: Is the psychosocial wellbeing affected in women and men shortly after allocation to a freeze-all strategy with postponement of embryo transfer compared to a fresh transfer strategy? SUMMARY ANSWER: In general, psychosocial wellbeing (i.e. emotional reactions to the treatment, quality-of-life, infertility-related stress, and marital benefit) was similar in women and men allocated to a freeze-all versus those allocated to a fresh-transfer strategy 6 days after disclosure of treatment strategy (i.e. 4 days after oocyte retrieval), although women in the freeze-all group reported a slightly higher degree of depressive symptoms and mood swings compared to women in the fresh transfer group. WHAT IS KNOWN ALREADY: The use of a freeze-all strategy, i.e. freezing of the entire embryo cohort followed by elective frozen embryo transfer in subsequent cycles has increased steadily over the past decade in assisted reproductive technology (ART). This strategy essentially eliminates the risk of ovarian hyperstimulation syndrome and has proven beneficial regarding some reproductive outcomes in subgroups of women. However, patients experience a longer time interval between oocyte retrieval and embryo transfer, hence a longer time to pregnancy, possibly adding additional stress to the ART treatment. So far, little focus has been on the possible psychosocial strains caused by postponement of embryo transfer. STUDY DESIGN, SIZE, DURATION: This is a self-reported questionnaire based sub-study of a multicentre randomized controlled trial (RCT) including 460 women and 396 male partners initiating their first, second, or third treatment cycle of invitro fertilisation or intracytoplasmic sperm injection (ICSI) from May 2016 to September 2018. This sub-study was included in the primary project protocol and project plan for the RCT, as psychosocial wellbeing was considered a secondary outcome. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women from eight public fertility clinics in Denmark and Sweden and one private clinic in Spain were randomized in a 1:1 ratio on the day of inclusion (menstrual cycle day 2 or 3) to either a freeze-all strategy with postponement of embryo transfer to a subsequent modified natural menstrual cycle or a fresh transfer strategy with embryo transfer in the hormone stimulated cycle. Treatment allocation was blinded until the day of the ovulation trigger. Women and their male partners were asked to complete a validated self-reported questionnaire 6 days after unblinding of treatment group allocation, corresponding to 4 days after oocyte retrieval, investigating their psychosocial wellbeing related to the treatment defined as emotional reactions to the treatment, quality-of-life, infertility-related stress, and marital benefit. The questionnaire included items from the Copenhagen Multi-Centre Psychosocial Infertility (COMPI) Fertility Problem Stress Scales and the COMPI Marital Benefit Measure. MAIN RESULTS AND THE ROLE OF CHANCE: Baseline characteristics were comparable between the two groups for both women and men. In total, response rates were 90.7% for women and 90.2% for men. In the freeze-all group, 207 women and 179 men completed the questionnaire compared with 204 women and 178 men in the fresh transfer group. Men in the two treatment groups did not differ in any of the explored aspects of psychosocial wellbeing (i.e. emotional reactions to the treatment, quality-of-life, infertility-related stress, and marital benefit) 6 days after disclosure of treatment strategy. Women in the freeze-all group reported a slightly higher degree of depressive symptoms (P = 0.045) and mood swings (P = 0.001) (i.e. variables included in 'emotional reactions to treatment') compared to women in the fresh transfer group. When adjusted for multiple testing, depressive symptoms were no longer significantly different between the two groups. No additional differences in psychosocial wellbeing were found. Self-reported quality-of-life during treatment was also rated as similar between the two groups in both women and men, but was slightly lower than they would rate their quality-of-life when not in fertility treatment. LIMITATIONS, REASONS FOR CAUTION: Although response rates were high, selection bias cannot be excluded. As this study was an RCT, we assume that psychosocial characteristics of the participants were equally distributed in the two groups, thus it is unlikely that the identified psychosocial differences between the freeze-all and fresh transfer group were present already at baseline. Furthermore, the questionnaire was completed as a one-time assessment 4 days after oocyte retrieval, thus not reflecting the whole treatment process, whereas an assessment after the full completed treatment cycle is needed to draw firm conclusions about the psychosocial consequences of the whole waiting period. However, a question posted that late would be highly biased on whether or not a pregnancy had been achieved. WIDER IMPLICATIONS OF THE FINDINGS: The results indicate that individuals in the freeze-all group exhibited slightly higher levels of depressive symptoms and mood swings compared to those in the fresh transfer group. Nevertheless, it is important to note that any worries related to potential emotional strains stemming from delaying embryo transfer should not overshadow the adoption of a freeze-all approach in cases where it is clinically recommended. As long as patients are provided with comprehensive information about the treatment strategy before initiating the process, it is worth emphasising that other aspects of psychosocial wellbeing were comparable between the two groups. STUDY FUNDING/COMPETING INTEREST(S): The study is part of the Reprounion collaborative study, co-financed by the European Union, Interreg V Öresund-Kattegat-Skagerrak. L.P. reports financial support from Merck A/S. H.S.N. reports grants from Freya Biosciences ApS, Ferring Pharmaceuticals, BioInnovation Institute, Ministry of Education, Novo Nordic Foundation, Augustinus Fonden, Oda og Hans Svenningsens Fond, Demant Fonden, Ole Kirks Fond and Independent Research Fund Denmark and personal fees from Ferring Pharmaceuticals, Merck A/S, Astra Zeneca, Cook Medical, IBSA Nordic and Gedeon Richter. H.S.N is founder and chairman of the Maternity Foundation and co-developed the Safe Delivery App (non-profit). N.C.F. reports grants from Gedeon Richter, Merck A/S, Cryos International and financial support from Ferring Pharmaceuticals, Merck A/S and Gedeon Richter. N.C.F. is chairman in the steering committee for the guideline groups for The Danish Fertility Society (non-profit). P.H. reports honoraria from Merch A/S, IBSA Nordic and Gedeon Richter. A.L.M.E. reports grants and financial support from Merck A/S and Gedeon Richter. A.P. reports grants from Gedeon Richter, Ferring Pharmaceuticals, Merck A/S and personal fees from Preglem S.A., Novo Nordic Foundation, Ferring Pharmaceuticals, Gedeon Richter, Cryos International, Merch A/S, Theramex and Organon and the lend of embryoscope to the institution from Gedeon Richter. All other authors declare no conflict of interest. TRIAL REGISTRATION NUMBER: Clinicaltrials.gov NCT02746562.

Impact of letrozole co-treatment during ovarian stimulation on oocyte yield, embryo development, and live birth rate in women with normal ovarian reserve: secondary outcomes from the RIOT trial.

STUDY QUESTION: Does letrozole (LZ) co-treatment during ovarian stimulation with gonadotropins for in IVF impact follicle recruitment, oocyte number and quality, embryo quality, or live birth rate (LBR)? SUMMARY ANSWER: No impact of LZ was found in follicle recruitment, number of oocytes, quality of embryos, or LBR. WHAT IS KNOWN ALREADY: Multi-follicle stimulation for IVF produces supra-physiological oestradiol levels. LZ is an aromatase inhibitor that lowers serum oestradiol thus reducing negative feedback and increasing the endogenous gonadotropins in both the follicular and the luteal phases, effectively normalizing the endocrine milieu during IVF treatment. STUDY DESIGN, SIZE, DURATION: Secondary outcomes from a randomized, double-blind placebo-controlled trial (RCT) investigating once-daily 5 mg LZ or placebo during stimulation for IVF with FSH. The RCT was conducted at four fertility clinics at University Hospitals in Denmark from August 2016 to November 2018 and pregnancy outcomes of frozen-thawed embryo transfers (FET) registered until May 2023. PARTICIPANTS/MATERIALS, SETTING, METHODS: One hundred fifty-nine women with expected normal ovarian reserve (anti-Müllerian hormone 8-32 nmol/l) were randomized to either co-treatment with LZ (n = 80) or placebo (n = 79). In total 1268 oocytes were aspirated developing into 386 embryos, and morphology and morphokinetics were assessed. One hundred twenty-nine embryos were transferred in the fresh cycle and 158 embryos in a subsequent FET cycle. The effect of LZ on cumulative clinical pregnancy rate (CPR), LBR, endometrial thickness in the fresh cycle, and total FSH consumption was reported. MAIN RESULTS AND THE ROLE OF CHANCE: The proportion of usable embryos of retrieved oocytes was similar in the LZ group and the placebo group with 0.31 vs 0.36 (mean difference (MD) -0.05, 95% CI (-0.12; 0.03), P = 0.65). The size and number of aspirated follicles at oocyte retrieval were similar with 11.8 vs 10.3 follicles per patient (MD 1.5, 95% CI (-0.5; 3.1), P = 0.50), as well as the number of retrieved oocytes with 8.0 vs 7.9 oocytes (MD 0.1, 95% CI (-1.4; 1.6), P = 0.39) in the LZ and placebo groups, respectively. The chance of retrieving an oocyte from the 13 to 16 mm follicles at trigger day was 66% higher (95% CI (24%; 108%), P = 0.002) in the placebo group than in the LZ group, whilst the chance of retrieving an oocyte from the ≥17 mm follicles at trigger day was 50% higher (95% CI (2%; 98%), P = 0.04) in the LZ group than in the placebo group. The proportion of fertilized oocytes with two-pronuclei per retrieved oocytes or per metaphase II oocytes (MII) (the 2PN rates) were similar regardless of fertilization with IVF or ICSI with 0.48 vs 0.57 (MD -0.09, 95% CI (-0.24; 0.04), P = 0.51), and 0.62 vs 0.64 (MD -0.02, 95% CI (-0.13; 0.07), P = 0.78) in the LZ and placebo groups, respectively. However, the MII rate in the ICSI group was significantly lower with 0.75 vs 0.88 in the LZ vs the placebo group (MD -0.14, 95% CI (-0.22; -0.06), P = 0.03). Blastocysts on Day 5 per patient were similar with 1.5 vs 2.0, P = 0.52, as well as vitrified blastocysts per patient Day 5 with 0.8 vs 1.2 in (MD -0.4, 95% CI (-1.0; 0.2), P = 0.52) and vitrified blastocysts per patient Day 6 with 0.6 vs 0.6 (MD 0, 95% CI (-0.3; 0.3), P = 1.00) in the LZ vs placebo group, respectively. Morphologic evaluation of all usable embryos showed a similar distribution in 'Good', 'Fair', and 'Poor', in the LZ vs placebo group, with an odds ratio (OR) of 0.8 95% CI (0.5; 1.3), P = 0.68 of developing a better class embryo. Two hundred and ninety-five of the 386 embryos were cultured in an embryoscope. Morphokinetic annotations showed that the odds of having a high KIDscore™ D3 Day 3 were 1.2 times higher (CI (0.8; 1.9), P = 0.68) in the LZ group vs the placebo group. The CPR per transfer was comparable with 31% vs 39% (risk-difference of 8%, 95% CI (-25%; 11%), P = 0.65) in the LZ and placebo group, respectively, as well as CPR per transfer adjusted for day of transfer, oestradiol and progesterone levels at trigger, progesterone levels mid-luteal, and number of oocytes retrieved (adjusted OR) of 0.8 (95% CI (0.4; 1.6), P = 0.72). Comparable LBR were found per transfer 28% vs 37% (MD -9%, 95% CI (-26%; 9%), P = 0.60) and per randomized women 24% vs 30% (MD of -6%, CI (-22%; 8%), P = 0.60) in the LZ group and placebo group, respectively. Furthermore, 4.8 years since the last oocyte aspiration, a total of 287 of 386 embryos have been transferred in the fresh or a subsequently FET cycle, disclosing the cumulative CPR, which is similar with 38% vs 34% (MD 95% CI (8%; 16%), P = 0.70) in the LZ vs placebo group. LIMITATIONS, REASONS FOR CAUTION: Both cleavage stage and blastocyst transfer and vitrification were permitted in the protocol, making it necessary to categorize their quality and pool the results. The study was powered to detect hormonal variation but not embryo or pregnancy outcomes. WIDER IMPLICATIONS OF THE FINDINGS: The similar utilization rate and quality of the embryos support the use of LZ co-treatment for IVF with specific indication as fertility preservation, patients with previous cancer, or poor responders. The effect of LZ on mature oocytes from different follicle sizes and LBRs should be evaluated in a meta-analysis or a larger RCT. STUDY FUNDING/COMPETING INTEREST(S): Funding was received from EU Interreg for ReproUnion, Sjaelland University Hospital, Denmark, Ferring Pharmaceuticals, and Gedeon Ricther. Roche Diagnostics contributed with assays. A.P. has received grants from Ferring, Merck Serono, and Gedeon Richter, consulting fees from Preglem, Novo Nordisk, Ferring, Gedeon Richter, Cryos, & Merck A/S, speakers fees from Gedeon Richter, Ferring, Merck A/S, Theramex, & Organon, and travel support from Gedeon Richter. The remaining authors declare that they have no competing interests in the research or publication. TRIAL REGISTRATION NUMBERS: NCT02939898 and NCT02946684.

Maternal Risk of Cardiovascular Disease After Use of Assisted Reproductive Technologies.

Importance: The use of assisted reproductive technologies (ARTs) is steadily increasing worldwide. The outcomes associated with treatment for an individual's long-term health, including risk of cardiovascular disease (CVD), remain largely unknown, due to the small number of studies and their limited follow-up time. Objective: To study whether the risk of CVD is increased among individuals who have given birth after ART compared with those who have given birth without ART. Design, Setting, and Participants: A registry-based cohort study was conducted using nationwide data from Denmark (1994-2014), Finland (1990-2014), Norway (1984-2015), and Sweden (1985-2015). Data analysis was conducted from January to August 2022. A total of 2 496 441 individuals with a registered delivery in the national birth registries during the study period were included, and 97 474 (4%) of these gave birth after ART. Exposures: Data on ART conception were available from ART quality registries and/or medical birth registries. Main Outcomes and Measures: Information on CVD was available from patient and cause of death registries. The risk of CVD was estimated with Cox proportional hazards regression, adjusting for age, calendar year of start of follow-up, parity, diagnosis of polycystic ovary syndrome, diabetes, chronic hypertension, and country. Results: Median follow-up was 11 (IQR, 5-18) years. The mean (SD) age of women with no use of ART was 29.1 (4.9) years, and the age of those who used ART was 33.8 (4.7) years. The rate of any CVD was 153 per 100 000 person-years. Individuals who gave birth after using ART had no increased risk of CVD (adjusted hazard ratio [AHR], 0.97; 95% CI, 0.91-1.02), with evidence of heterogeneity between the countries (I2 = 76%; P = .01 for heterogeneity). No significant differences in the risk of ischemic heart disease, cerebrovascular disease, stroke, cardiomyopathy, heart failure, pulmonary embolism, or deep vein thrombosis were noted with use of ART. However, there was a tendency for a modest reduction in the risk of myocardial infarction (AHR, 0.80; 95% CI, 0.65-0.99), with no notable heterogeneity between countries. Conclusions and Relevance: The findings of this study suggest that women who gave birth after ART were not at increased risk of CVD over a median follow-up of 11 years compared with those who conceived without ART. Longer-term studies are needed to further examine whether ART is associated with higher risk of CVD.

Does luteal phase progesterone supplementation affect physical and psychosocial well-being among women undergoing modified natural cycle-FET? A sub-study of a randomized controlled trial.

STUDY QUESTION: Are there any differences in physical and psychosocial well-being among women undergoing modified natural cycle frozen embryo transfer (mNC-FET) with or without vaginal progesterone as luteal phase support (LPS)? SUMMARY ANSWER: Women undergoing mNC-FET with vaginal progesterone supplementation were more likely to experience physical discomfort but there was no difference in psychosocial well-being between the two groups. WHAT IS KNOWN ALREADY: mNC-FET can be carried out with or without vaginal progesterone as LPS, which has several side-effects. It is commonly known that fertility treatment can cause stress and psychosocial strain, however, most studies on this subject are conducted in fresh cycle regimes, which differ from NC-FET and results may not be comparable. STUDY DESIGN, SIZE, DURATION: This is a sub-study of an ongoing RCT investigating whether progesterone supplementation has a positive effect on live birth rate in mNC-FET. The RCT is conducted at eight fertility clinics in Denmark from 2019 and is planned to end primo 2024. The sub-study is based on two questionnaires on physical and psychosocial well-being added to the RCT in August 2019. On the time of data extraction 286 women had answered both questionnaires. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women who had answered both questionnaires were included in the sub-study. Participants were equally distributed, with 143 in each of the two groups. Participants in both groups received the same questionnaires at two time-points: on cycle day 2-5 (baseline) and after blastocyst transfer. Participants in the progesterone group had administered progesterone for 7 days upon answering the second questionnaire. All items in the questionnaires were validated. Items on psychosocial well-being originate from the Copenhagen Multi-Centre Psychosocial Infertility-Fertility Problem Stress Scale (COMPI-FPSS) and from the Mental Health Inventory-5. MAIN RESULTS AND THE ROLE OF CHANCE: Women receiving progesterone experienced more vaginal itching and/or burning than women in the non-progesterone group (P < 0.001). Women in the progesterone group also experienced more self-reported vaginal yeast infection, this was, however, not significant after adjustment for multiple testing (P/adjusted P = 0.049/0.881). No differences regarding psychosocial well-being were found between the two groups. Within the progesterone group, a shift toward feeling less 'downhearted and blue' was found when comparing response distribution at baseline and after blastocyst transfer (P < 0.001). LIMITATIONS, REASONS FOR CAUTION: All items on physical symptoms were self-reported. The item on vaginal yeast infection was therefore not diagnosed by a doctor. Inclusion in the study required a few extra visits to the clinic, participants who felt more burdened by fertility treatment might have been more likely to decline participation. Women who experienced a lot of side-effects to progesterone prior to this FET cycle, might be less likely to participate. WIDER IMPLICATIONS OF THE FINDINGS: Our results are in line with previous known side-effects to progesterone. Physical side-effects of progesterone should be considered before administration. STUDY FUNDING/COMPETING INTEREST(S): The RCT is fully supported by Rigshospitalet's Research Foundation and a grant from Gedeon Richter. Gedeon Richter were not involved in the design of protocol nor in the conduction of the study or analysis of results. A.P., L.P., and N.I.-C.F. report grants from Gedeon Richter, Ferring and Merck with no relations to this study. N.I.-C.F. has received travel support from Ferring, Merck A/S, & Gideon Richter, and is the head of the steering committee for the Danish Fertility Guidelines made by the members of from the Danish Fertility Society. A.P. reports consulting fees from Preglem, Novo Nordisk, Ferring, Gedeon Richter, Cryos, & Merck A/S, honoraria from Gedeon Richter, Ferring, Merck A/S, Theramex, and Organon, has received travel support from Gedeon Richter (payment to institution), participated on an advisory board for Preglem and was loaned an embryoscope from Gedeon Richter to their institution. A.L.S. has stock options for Novo Nordisk B A/S. B.A. have received unrestricted grant from Gedeon Richter Nordic and Merck and honoraria for lectures from Gedeon Richter, Merck, IBSA, and Marckyrl Pharma. TRIAL REGISTRATION NUMBER: The RCT is registered on ClinicalTrials. gov (NCT03795220) and in EudraCT (2018-002207-34).

Risk of congenital malformations in live-born singletons conceived after intracytoplasmic sperm injection: a Nordic study from the CoNARTaS group.

OBJECTIVE: To investigate whether the risk of major congenital malformations is higher in live-born singletons conceived with intracytoplasmic sperm injection (ICSI) compared with in vitro fertilization (IVF)? DESIGN: Nordic register-based cohort study. SETTING: Cross-linked data from Medical Birth Registers and National ART and Patient Registers in Denmark, Norway and Sweden. Data were included from the year the first child conceived using ICSI was born: Sweden, 1992; Denmark, 1994; and Norway, 1996. Data were included until 2014 for Denmark and 2015 for Norway and Sweden. PATIENT(S): All live-born singletons conceived using fresh ICSI (n = 32,484); fresh IVF (n = 47,178); without medical assistance (n = 4,804,844); and cryo-ICSI (n = 7,200) during the study period. INTERVENTION(S): Different in vitro conception methods, and cryopreservation of embryos. MAIN OUTCOME MEASURE(S): Risk of major congenital malformations on the basis of International Classification of Diseases codes. The European Concerted Action on Congenital Anomalies and Twins was used to differentiate between major and minor malformations. RESULT(S): Among singletons conceived using fresh ICSI, 6.0% had a major malformation, compared with 5.3% of children conceived using fresh IVF; 4.2% of children conceived without medical assistance; and 4.9% of children conceived using cryo-ICSI; adjusted odds ratio (AOR) 1.07 (95% confidence interval [CI] 1.01-1.14) in ICSI vs. IVF; and AOR 1.28 (95% CI, 1.23-1.35) in ICSI vs. no medical assistance; and AOR 1.11 (95% CI, 0.99-1.26) in ICSI fresh vs. cryo-ICSI. When malformations were grouped by different organ systems, children conceived using ICSI had a higher risk of respiratory and chromosomal malformations compared with children conceived using IVF, but there were very few cases in each group. When categorizing children conceived using ICSI according to treatment indication (male factor infertility only vs. other indications), we found a higher risk of hypospadias when ICSI was performed because of male factor infertility only (AOR 1.85 [95% CI 1.03-332]). The indications for ICSI changed over time, as male factor infertility did not remain the primary indication for ICSI throughout the study period. CONCLUSION(S): In this large cohort study, we found the risk of major malformations in live-born singletons to be slightly higher after fresh ICSI compared with fresh IVF. These findings should be considered when choosing the assisted reproductive technology method for couples without male factor infertility.

Endometrial scratching in women undergoing IVF/ICSI: an individual participant data meta-analysis.

BACKGROUND: In IVF/ICSI treatment, the process of embryo implantation is the success rate-limiting step. Endometrial scratching has been suggested to improve this process, but it is unclear if this procedure increases the chance of implantation and live birth (LB) and, if so, for whom, and how the scratch should be performed. OBJECTIVE AND RATIONALE: This individual participant data meta-analysis (IPD-MA) aims to answer the question of whether endometrial scratching in women undergoing IVF/ICSI influences the chance of a LB, and whether this effect is different in specific subgroups of women. After its incidental discovery in 2000, endometrial scratching has been suggested to improve embryo implantation. Numerous randomized controlled trials (RCTs) have been conducted, showing contradicting results. Conventional meta-analyses were limited by high within- and between-study heterogeneity, small study samples, and a high risk of bias for many of the trials. Also, the data integrity of several trials have been questioned. Thus, despite numerous RCTs and a multitude of conventional meta-analyses, no conclusion on the clinical effectiveness of endometrial scratching could be drawn. An IPD-MA approach is able to overcome many of these problems because it allows for increased uniformity of outcome definitions, can filter out studies with data integrity concerns, enables a more precise estimation of the true treatment effect thanks to adjustment for participant characteristics and not having to make the assumptions necessary in conventional meta-analyses, and because it allows for subgroup analysis. SEARCH METHODS: A systematic literature search identified RCTs on endometrial scratching in women undergoing IVF/ICSI. Authors of eligible studies were invited to share original data for this IPD-MA. Studies were assessed for risk of bias (RoB) and integrity checks were performed. The primary outcome was LB, with a one-stage intention to treat (ITT) as the primary analysis. Secondary analyses included as treated (AT), and the subset of women that underwent an embryo transfer (AT+ET). Treatment-covariate interaction for specific participant characteristics was analyzed in AT+ET. OUTCOMES: Out of 37 published and 15 unpublished RCTs (7690 participants), 15 RCTs (14 published, one unpublished) shared data. After data integrity checks, we included 13 RCTs (12 published, one unpublished) representing 4112 participants. RoB was evaluated as 'low' for 10/13 RCTs. The one-stage ITT analysis for scratch versus no scratch/sham showed an improvement of LB rates (odds ratio (OR) 1.29 [95% CI 1.02-1.64]). AT, AT+ET, and low-RoB-sensitivity analyses yielded similar results (OR 1.22 [95% CI 0.96-1.54]; OR 1.25 [95% CI 0.99-1.57]; OR 1.26 [95% CI 1.03-1.55], respectively). Treatment-covariate interaction analysis showed no evidence of interaction with age, number of previous failed embryo transfers, treatment type, or infertility cause. WIDER IMPLICATIONS: This is the first meta-analysis based on IPD of more than 4000 participants, and it demonstrates that endometrial scratching may improve LB rates in women undergoing IVF/ICSI. Subgroup analysis for age, number of previous failed embryo transfers, treatment type, and infertility cause could not identify subgroups in which endometrial scratching performed better or worse. The timing of endometrial scratching may play a role in its effectiveness. The use of endometrial scratching in clinical practice should be considered with caution, meaning that patients should be properly counseled on the level of evidence and the uncertainties.

Childhood BMI after ART with frozen embryo transfer.

STUDY QUESTION: Does BMI at 7-10 years of age differ in children conceived after frozen embryo transfer (FET) compared to children conceived after fresh embryo transfer (fresh-ET) or natural conception (NC)? SUMMARY ANSWER: BMI in childhood does not differ between children conceived after FET compared to children conceived after fresh-ET or NC. WHAT IS KNOWN ALREADY: High childhood BMI is strongly associated with obesity and cardiometabolic disease and mortality in adulthood. Children conceived after FET have a higher risk of being born large for gestational age (LGA) than children conceived after NC. It is well-documented that being born LGA is associated with an increased risk of obesity in childhood, and it has been hypothesized that ART induces epigenetic variations around fertilization, implantation, and early embryonic stages, which influence fetal size at birth as well as BMI and health later in life. STUDY DESIGN, SIZE, DURATION: The study 'Health in Childhood following Assisted Reproductive Technology' (HiCART) is a large retrospective cohort study with 606 singletons aged 7-10 years divided into three groups according to mode of conception: FET (n = 200), fresh-ET (n = 203), and NC (n = 203). All children were born in Eastern Denmark from 2009 to 2013 and the study was conducted from January 2019 to September 2021. PARTICIPANTS/MATERIALS, SETTING, METHODS: We anticipated that the participation rate would differ between the three study groups owing to variation in the motivation to engage. To reach the goal of 200 children in each group, we invited 478 in the FET-group, 661 in the fresh-ET-group, and 1175 in the NC-group. The children underwent clinical examinations including anthropometric measurements, whole-body dual-energy x-ray absorptiometry-scan, and pubertal staging. Standard deviation scores (SDS) were calculated for all anthropometric measurements using Danish reference values. Parents completed a questionnaire regarding the pregnancy and the current health of the child and themselves. Maternal, obstetric, and neonatal data were obtained from the Danish IVF Registry and Danish Medical Birth Registry. MAIN RESULTS AND THE ROLE OF CHANCE: As expected, children conceived after FET had a significantly higher birthweight (SDS) compared to both children born after fresh-ET (mean difference 0.42, 95% CI (0.21; 0.62)) and NC (mean difference 0.35, 95% CI (0.14; 0.57)). At follow-up (7-10 years), no differences were found in BMI (SDS) comparing FET to fresh-ET, FET to NC, and fresh-ET to NC. Similar results were also found regarding the secondary outcomes weight (SDS), height (SDS), sitting height, waist circumference, hip circumference, fat, and fat percentage. In the multivariate linear regression analyses, the effect of mode of conception remained non-significant after adjusting for multiple confounders. When stratified on sex, weight (SDS), and height (SDS) were significantly higher for girls born after FET compared to girls born after NC. Further, FET-girls also had significantly higher waist, hip, and fat measurements compared to girls born after fresh-ET. However, for the boys the differences remained insignificant after confounder adjustment. LIMITATIONS, REASONS FOR CAUTION: The sample size was decided in order to detect a difference of 0.3 SDS in childhood BMI (which corresponds to an adult cardiovascular mortality hazard ratio of 1.034). Thus, smaller differences in BMI SDS may be overlooked. As the overall participation rate was 26% (FET: 41%, fresh-ET: 31%, NC: 18%), selection bias cannot be excluded. Regarding the three study groups, many possible confounders have been included but there might be a small risk of selection bias as information regarding cause of infertility is not available in this study. WIDER IMPLICATIONS OF THE FINDINGS: The increased birthweight in children conceived after FET did not translate into differences in BMI, however, for the girls born after FET, we observed increased height (SDS) and weight (SDS) compared to the girls born after NC, while for the boys the results remained insignificant after confounder adjustment. Since body composition in childhood is a strong biomarker of cardiometabolic disease later in life, longitudinal studies of girls and boys born after FET are needed. STUDY FUNDING/COMPETING INTEREST(S): The study was funded by the Novo Nordisk Foundation (grant number: NNF18OC0034092, NFF19OC0054340) and Rigshospitalets Research Foundation. There were no competing interests. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier: NCT03719703.

The future of frozen-thawed embryo transfer in hormone replacement therapy cycles.

PURPOSE OF REVIEW: This review focuses on the efficacy of letrozole stimulated frozen-thawed embryo transfer (FET) compared to hormone replacement therapy (HRT) FET in women with polycystic ovarian syndrome (PCOS) and/or oligo-anovulation. Further, obstetric and perinatal risks in HRT FET are summarized. RECENT FINDINGS: The presence of a corpus luteum seems to reduce the risk of pregnancy-related hypertension and preeclampsia after FET. As a natural cycle (NC) FET is not an option for women with oligo-/amenorrhea these women may benefit from FET with mild stimulation compared to HRT FET. The intention of mild stimulation in anovulatory women is to induce (mono) ovulation to mimic the endocrine profiles of the natural cycle and the early pregnancy after natural conception. Mild stimulation by letrozole is patient friendly and cheap compared to gonadotropin stimulated FET and has been increasingly used in recent years. Although the quality of evidence is low, the pregnancy outcomes after letrozole FET seems similar or even better compared to HRT FET in women with PCOS and/or oligo-anovulation. SUMMARY: Natural and modified NC FET should be used whenever possible to mitigate adverse obstetric and perinatal outcomes after HRT FET. For anovulatory women, whenever ovulation can be induced, we advocate the use of mild stimulation FET to create a corpus luteum awaiting results from RCTs limited to oligo-anovulatory women.

Fertility preservation in women with benign gynaecological conditions.

Although a wealth of data has been published regarding fertility preservation (FP) in women with malignant diseases who receive gonadotoxic treatment, the role of FP in non-malignant conditions has been studied to a much lesser extent. These include benign haematological, autoimmune, and genetic disorders, as well as a multitude of benign gynaecological conditions (BGCs) that may compromise ovarian reserve and/or reproductive potential due to pathogenic mechanisms or as a result of medical or surgical treatments. Alongside accumulating data that document the reproductive potential of cryopreserved oocytes and ovarian tissue, there is potential interest in FP for women with BGCs at risk of infertility; however, there are currently insufficient data about FP in women with BGCs to develop guidelines for clinical practice. The purpose of this article is to appraise the available evidence regarding FP for BGC and discuss potential strategies for FP based on estimated ovarian impairment and on short-term and long-term reproductive goals of patients. Cost-effectiveness considerations and patients' perspectives will also be discussed.

Long-term outcomes for children conceived by assisted reproductive technology.

Worldwide, more than 10 million children have been born after assisted reproduction technology (ART), comprising up to 7.9% of children born in Europe and up to 5.1 % of children born in the US in 2018. The short-term outcome for children born after ART is well-known from numerous publications, with higher rates of preterm birth and low birth weight in children born after fresh embryo transfer and higher rates of large for gestational age and high birth weight in children born after frozen embryo transfer compared with children born after spontaneous conception. Higher rates of birth defects in children born after ART have also been shown consistently over time. Studies on long-term health outcomes after ART are scarcer but suggest an increased risk of altered blood pressure and cardiovascular function in children born after ART. In this review, we summarize long-term health outcomes in children born after ART and discuss whether the increased health risks are associated with intrinsic maternal or paternal factors related to subfertility or ART treatments per se. Finally, we speculate where the future will bring us regarding ART treatment strategies and the safety of the mother and child.

The time has come for harmonized international ART registration.

For more than two decades, the European IVF-Monitoring Consortium has collected data on IVF in Europe with the aim of monitoring the quality and safety of assisted reproductive technology (ART) treatments, to ensure the highest performance with the lowest risk for patients and their offspring. Likewise, the Society for Assisted Reproductive Technology in the USA and the Australia/New Zealand Assisted Reproduction Database collect, process and publish data in their regions. The better the legal framework for ART surveillance, the more complete and reliable are the datasets. Worldwide, the landscape of ART regulation is fragmented, and until there is a legal obligation to report ART data in all countries, with an appropriate quality control of the data collected, the reported outcomes should be interpreted with caution. Once uniform and harmonized data are achieved, consensus reports based on collective findings can begin to address key topics such as cycle segmentation and complications. Improved registration systems and datasets allowing optimized surveillance should be developed in collaboration with patient representatives to consider patients' needs, especially aiming to provide higher transparency around ART services. Support from national and international reproductive medicine societies will also be essential to the future evolution of ART registries.