Relationships between mothers and children in families formed by shared biological motherhood.

STUDY QUESTION: Does shared biological motherhood, in which a woman gives birth to the genetic child of her female partner, result in more positive mother-child relationships than donor insemination, in which only one mother is biologically related to the child? SUMMARY ANSWER: Mothers in both family types showed high levels of bonding with their children and viewed their relationship with their child positively. WHAT IS KNOWN ALREADY: There is some evidence of feelings of inequality regarding their relationship with their child between biological and non-biological mothers in lesbian mother families formed by donor insemination, with a qualitative longitudinal study showing a tendency for children to form stronger bonds with their biological than their non-biological mother. STUDY DESIGN, SIZE, DURATION: Thirty lesbian mother families created through shared biological motherhood were compared with 30 lesbian mother families formed by donor-IVF. All families had two mothers who both participated in the study, and the children were aged from infancy up to 8 years old. Data collection took place over 20 months beginning in December 2019. PARTICIPANTS/MATERIALS, SETTING, METHODS: Each mother in the family was interviewed separately using the Parent Development Interview (PDI), a reliable and valid measure of the nature of the parent's emotional bond with their child. The interviews were transcribed verbatim and coded separately by one of two trained researchers who were unaware of the child's family type. The interview produces 13 variables that relate to the parent's representations of themselves as a parent, 5 variables that relate to the parent's representations of the child, and a global variable that assesses the extent to which the parent can reflect on the child and their relationship. MAIN RESULTS AND THE ROLE OF CHANCE: Families formed through shared biological parenthood did not differ from families created by donor-IVF in terms of the quality of mothers' relationships with their children as assessed by the PDI. Neither were differences identified between birth mothers and non-birth mothers across the entire sample, or between gestational and genetic mothers within the families formed by shared biological parenthood. Multivariate analyses were conducted to minimize the role of chance. LIMITATIONS, REASONS FOR CAUTION: Ideally, larger samples of families and a narrower age range of children would have been studied, but this was not possible as we were reliant on the small number of families formed through shared biological motherhood in the UK when the study began. To maintain the anonymity of the families, it was not possible to request information from the clinic that may have shed light on differences between those who responded to the request to participate and those who did not. WIDER IMPLICATIONS OF THE FINDINGS: The findings show that shared biological motherhood is a positive option for lesbian couples who wish to have a more equal biological relationship to their children. One type of biological connection does not appear to have a greater influence on the quality of parent-child relationships than the other. STUDY FUNDING/COMPETING INTEREST(S): This study was funded by the Economic and Social Research Council (ESRC) grant ES/S001611/1. KA is Director, and NM is Medical Director, of the London Women's Clinic. The remaining authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: N/A.

Elective freezing of embryos versus fresh embryo transfer in IVF: a multicentre randomized controlled trial in the UK (E-Freeze).

STUDY QUESTION: Does a policy of elective freezing of embryos, followed by frozen embryo transfer result in a higher healthy baby rate, after first embryo transfer, when compared with the current policy of transferring fresh embryos? SUMMARY ANSWER: This study, although limited by sample size, provides no evidence to support the adoption of a routine policy of elective freeze in preference to fresh embryo transfer in order to improve IVF effectiveness in obtaining a healthy baby. WHAT IS KNOWN ALREADY: The policy of freezing all embryos followed by frozen embryo transfer is associated with a higher live birth rate for high responders but a similar/lower live birth after first embryo transfer and cumulative live birth rate for normal responders. Frozen embryo transfer is associated with a lower risk of ovarian hyperstimulation syndrome (OHSS), preterm delivery and low birthweight babies but a higher risk of large babies and pre-eclampsia. There is also uncertainty about long-term outcomes, hence shifting to a policy of elective freezing for all remains controversial given the delay in treatment and extra costs involved in freezing all embryos. STUDY DESIGN, SIZE, DURATION: A pragmatic two-arm parallel randomized controlled trial (E-Freeze) was conducted across 18 clinics in the UK from 2016 to 2019. A total of 619 couples were randomized (309 to elective freeze/310 to fresh). The primary outcome was a healthy baby after first embryo transfer (term, singleton live birth with appropriate weight for gestation); secondary outcomes included OHSS, live birth, clinical pregnancy, pregnancy complications and cost-effectiveness. PARTICIPANTS/MATERIALS, SETTING, METHODS: Couples undergoing their first, second or third cycle of IVF/ICSI treatment, with at least three good quality embryos on Day 3 where the female partner was ≥18 and <42 years of age were eligible. Those using donor gametes, undergoing preimplantation genetic testing or planning to freeze all their embryos were excluded. IVF/ICSI treatment was carried out according to local protocols. Women were followed up for pregnancy outcome after first embryo transfer following randomization. MAIN RESULTS AND THE ROLE OF CHANCE: Of the 619 couples randomized, 307 and 309 couples in the elective freeze and fresh transfer arms, respectively, were included in the primary analysis. There was no evidence of a statistically significant difference in outcomes in the elective freeze group compared to the fresh embryo transfer group: healthy baby rate {20.3% (62/307) versus 24.4% (75/309); risk ratio (RR), 95% CI: 0.84, 0.62 to 1.15}; OHSS (3.6% versus 8.1%; RR, 99% CI: 0.44, 0.15 to 1.30); live birth rate (28.3% versus 34.3%; RR, 99% CI 0.83, 0.65 to 1.06); and miscarriage (14.3% versus 12.9%; RR, 99% CI: 1.09, 0.72 to 1.66). Adherence to allocation was poor in the elective freeze group. The elective freeze approach was more costly and was unlikely to be cost-effective in a UK National Health Service context. LIMITATIONS, REASONS FOR CAUTION: We have only reported on first embryo transfer after randomization; data on the cumulative live birth rate requires further follow-up. Planned target sample size was not obtained and the non-adherence to allocation rate was high among couples in the elective freeze arm owing to patient preference for fresh embryo transfer, but an analysis which took non-adherence into account showed similar results. WIDER IMPLICATIONS OF THE FINDINGS: Results from the E-Freeze trial do not lend support to the policy of electively freezing all for everyone, taking both efficacy, safety and costs considerations into account. This method should only be adopted if there is a definite clinical indication. STUDY FUNDING/COMPETING INTEREST(S): NIHR Health Technology Assessment programme (13/115/82). This research was funded by the National Institute for Health Research (NIHR) (NIHR unique award identifier) using UK aid from the UK Government to support global health research. The views expressed in this publication are those of the author(s) and not necessarily those of the NIHR or the UK Department of Health and Social Care. J.L.B., C.C., E.J., P.H., J.J.K., L.L. and G.S. report receipt of funding from NIHR, during the conduct of the study. J.L.B., E.J., P.H., K.S. and L.L. report receipt of funding from NIHR, during the conduct of the study and outside the submitted work. A.M. reports grants from NIHR personal fees from Merck Serono, personal fees for lectures from Merck Serono, Ferring and Cooks outside the submitted work; travel/meeting support from Ferring and Pharmasure and participation in a Ferring advisory board. S.B. reports receipt of royalties and licenses from Cambridge University Press, a board membership role for NHS Grampian and other financial or non-financial interests related to his roles as Editor-in-Chief of Human Reproduction Open and Editor and Contributing Author of Reproductive Medicine for the MRCOG, Cambridge University Press. D.B. reports grants from NIHR, during the conduct of the study; grants from European Commission, grants from Diabetes UK, grants from NIHR, grants from ESHRE, grants from MRC, outside the submitted work. Y.C. reports speaker fees from Merck Serono, and advisory board role for Merck Serono and shares in Complete Fertility. P.H. reports membership of the HTA Commissioning Committee. E.J. reports membership of the NHS England and NIHR Partnership Programme, membership of five Data Monitoring Committees (Chair of two), membership of six Trial Steering Committees (Chair of four), membership of the Northern Ireland Clinical Trials Unit Advisory Group and Chair of the board of Oxford Brain Health Clinical Trials Unit. R.M. reports consulting fees from Gedeon Richter, honorarium from Merck, support fees for attendance at educational events and conferences for Merck, Ferring, Bessins and Gedeon Richter, payments for participation on a Merck Safety or Advisory Board, Chair of the British Fertility Society and payments for an advisory role to the Human Fertilisation and Embryology Authority. G.S. reports travel and accommodation fees for attendance at a health economic advisory board from Merck KGaA, Darmstadt, Germany. N.R.-F. reports shares in Nurture Fertility. Other authors' competing interests: none declared. TRIAL REGISTRATION NUMBER: ISRCTN: 61225414. TRIAL REGISTRATION DATE: 29 December 2015. DATE OF FIRST PATIENT'S ENROLMENT: 16 February 2016.

The true incidence of recurrent implantation failure.

PURPOSE OF REVIEW: To review the merits and limitations of current definitions of recurrent implantation failure (RIF), how they translate into estimates of incidence and to summarize how emerging concepts of individualizing the recognition of this condition can assist in changing the way RIF is identified, studied and managed. RECENT FINDINGS: The notion of a one size fits all definition of RIF is seen to be of limited clinical value, as the individual risk of repeated IVF failure has many determinants and causes. Novel approaches provide a means of identifying 'actionable' RIF in individual patients. SUMMARY: Uncertainties as to what constitutes, causes and defines RIF have served to limit progress in its management. A new approach promises to permit progress from the current impasse.

Peri-implantation glucocorticoid administration for assisted reproductive technology cycles.

BACKGROUND: The use of peri-implantation glucocorticoids has been advocated to improve embryo implantation during assistive reproductive technology (ART) cycles such as in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI). It has been proposed that glucocorticoids may improve the intrauterine environment by acting as immunomodulators to reduce the uterine natural killer (NK) cell count and activity, normalising the cytokine expression profile in the endometrium and by suppression of endometrial inflammation. OBJECTIVES: To evaluate the effectiveness and safety of glucocorticoids versus no glucocorticoids administered around the time of anticipated implantation in women undergoing IVF or ICSI. SEARCH METHODS: We searched the Cochrane Gynaecology and Fertility (CGF) Group specialised register, CENTRAL (now also containing output from two trial registers and CINAHL), MEDLINE and Embase, on 20 December 2021, together with reference checking, contact with experts in the field and relevant conference proceedings to identify additional studies. This review is an update of the review first published in  2007 and last updated in 2012. SELECTION CRITERIA: Randomised controlled trials (RCTs) comparing the efficacy of supplementary systemic administration of glucocorticoids in the peri-implantation period with a placebo or no glucocorticoids in subfertile women undergoing IVF or ICSI were included. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures recommended by Cochrane. The primary review outcomes were live birth rate and multiple pregnancy. MAIN RESULTS: We included 16 RCTs (2232 couples analysed). We are uncertain whether glucocorticoids improved live birth rates (odds ratio (OR) 1.37, 95% confidence interval (CI) 0.69 to 2.71; 2 RCTs, n = 366; I2 = 7%; very low-certainty evidence). This suggests that if the chance of live birth following no glucocorticoids/placebo is assumed to be 9%, the chance following glucocorticoids would be between 6% and 21%. We are also uncertain whether there was a difference between peri-implantation glucocorticoids on multiple pregnancy rates per couple (OR 0.86, 95% CI 0.33 to 2.20; 4 RCTs, n = 504; I2 = 53%; very low-certainty evidence). The I2 of 53% may represent moderate statistical heterogeneity and results have to be interpreted with caution. With regard to pregnancy rates, we are uncertain whether there was a difference between ongoing pregnancy rates after glucocorticoids versus no glucocorticoids/placebo (OR 1.19, 95% CI 0.80 to 1.76; 3 RCTs, n = 476; I2 = 0%; very low-certainty evidence) and clinical pregnancy rates after glucocorticoids versus no glucocorticoids/placebo (OR 1.17, 95% CI 0.95 to 1.44; 13 RCTs, n = 1967; I2 = 0%; low-certainty evidence). This suggests that if the chance of clinical pregnancy following no glucocorticoids/placebo is assumed to be 25%, the chance following glucocorticoids would be between 24% and 32%. Furthermore, we are also uncertain whether peri-implantation glucocorticoids influenced miscarriage rates per couple (OR 1.09, 95% CI 0.63 to 1.87; 6 RCTs, n = 821; I2 = 0%; very low-certainty evidence), the incidence of ectopic pregnancies per couple (OR 2.28, 95% CI 0.33 to 15.62; 3 RCTs, n = 320; I2 = 0%; very low-certainty evidence) and ovarian hyperstimulation syndrome (OHSS) per couple (OR 1.07, 95% CI 0.60 to 1.90; 3 RCTs, n = 370; I2 = 0%; very low-certainty evidence) compared to no glucocorticoids/placebo. The evidence was very low to low certainty: the main limitations were serious risk of bias due to poor reporting of study methods, and serious imprecision. AUTHORS' CONCLUSIONS: Overall, there was insufficient evidence that administration of peri-implantation glucocorticoids in IVF/ICSI cycles influenced clinical outcomes. These findings were limited to the routine use of glucocorticoids in subfertile women undergoing IVF or ICSI.

Smartphone-based lifestyle coaching modifies behaviours in women with subfertility or recurrent miscarriage: a randomized controlled trial.

RESEARCH QUESTION: Is an online lifestyle coaching platform more effective at modifying periconceptional behaviours than standard advice offered by the UK National Health Service (NHS)? DESIGN: Women with subfertility or recurrent miscarriage were recruited to a two-centre randomized controlled trial. They were randomized to either the online lifestyle coaching platform Smarter Pregnancy (intervention) or periconceptional advice provided by NHS websites (control). Participants completed a lifestyle questionnaire at baseline, 6, 12, 18 and 24 weeks, and the results were used to tailor lifestyle coaching in the intervention group. At baseline, 12 and 24 weeks, composite risk scores (CRS) were calculated. A lower CRS corresponds to a healthier lifestyle. RESULTS: Of the 400 women recruited, 262 women were randomized (131 in each arm). At 12 weeks, a reduction in CRS (includes risk score for intake of folic acid, vegetables and fruits, smoking and alcohol) was observed in the intervention versus control arms. After correcting for baseline, the difference in the CRS between intervention and control was -0.47 (95% CI -0.97 to 0.02) at 12 weeks and -0.32 (95% CI -0.82 to 0.15) at 24 weeks. A statistically significant reduction in lifestyle risk scores was found in women with a body mass index (BMI) of 25 kg/m2 or above compared with those with a BMI below 25kg/m2. The odds of being pregnant at 24 weeks was increased in the intervention versus control (OR 2.83, 95% CI 0.35 to 57.76). CONCLUSIONS: The Smarter Pregnancy coaching platform is more effective in delivering lifestyle advice and modulating behaviours to support women with a history of subfertility or recurrent miscarriage than standard online NHS advice.

Embryos are exposed to a significant drop in temperature during the embryo transfer procedure: a pilot study.

RESEARCH QUESTION: During the embryo transfer procedure, to what degree of temperature drop are embryos exposed to between loading the transfer catheter and placing it into the uterus? DESIGN: Twenty-nine simulated embryo transfer procedures were carried out across five clinics. A thermocouple probe was used for standardized measurements inside the embryo transfer catheter to investigate the change in temperature that occurred in the time period between loading and placing the catheter in the uterus. RESULTS: In all cases, the temperature at the loaded catheter tip fell rapidly to ambient temperature during transit from the embryo transfer workstation in the laboratory to the procedure room, even though embryo transfer procedures, ambient temperatures and embryo transfer catheter temperatures at loading varied between clinics. CONCLUSIONS: Given the sensitivity of the pre-implantation embryo to its immediate environment, the rapid and profound drop in temperature observed at the catheter tip that houses the embryo during transit from laboratory to the uterus may affect embryo viability and health. This issue should be addressed to ensure that the tight temperature control aimed for by IVF laboratories continues throughout the embryo transfer procedure, and could improve clinical outcomes.

Factors predicting clinical outcomes from 494 vitrified oocyte donation cycles at a UK-regulated egg bank.

RESEARCH QUESTION: Do donor age, AMH, AFC, BMI and reproductive history predict response to ovarian stimulation? Do donor and recipient clinical markers and embryology parameters predict recipient pregnancy and live birth? DESIGN: Retrospective cohort study of 494 altruistic oocyte donors aged 18-35 years; 340 were matched to 559 recipients. Predictors of donor total oocyte yield and total mature oocyte yield were identified. Total and mature oocyte number were compared according to stratified donor AMH and age. Donor, recipient and embryology parameters predictive of recipient primary outcomes (clinical pregnancy and live birth) were identified. RESULTS: Donor age and AMH predicted total oocyte yield (P = 0.030 and P < 0.001)) and total mature oocyte yield (P = 0.011 and P < 0.001). Donors aged 30-35 years with AMH 15-29.9 pmol/l had lower total oocyte yield (P = 0.004) and mature oocyte yield (P < 0.001) than donors aged 18-24 years. Up to an AMH threshold of 39.9 pmol/l, increasing AMH levels predicted higher total oocyte yield (<15 pmol/l versus 15-29.9 pmol/l, P = 0.001; 15-29.9 pmol/l versus 30-39.9 pmol/l, P < 0.001; 30-39.9pmol/l versus ≥ 40 pmol/l, P = 1.0) and mature oocyte yield (<15 pmol/l versus 15-29.9 pmol/l, P = 0.005; 15-29.9 pmol/l versus 30-39.9 pmol/l, P = 0.006; 30-39.9 pmol/l versus ≥40 pmol/l, P = 1.0). In recipients, the rate of transferrable embryos per oocytes received, fertilized and number of embryo transfers needed to achieve the primary outcome were predictors of cumulative clinical pregnancy (P = 0.011, P = 0.017 and P < 0.001) and live birth (P = 0.008, P = 0.012 and P < 0.001) rates. Recipient BMI (P = 0.024) and previous miscarriages (P = 0.045) were predictors of cumulative live birth rate. Donor age 18-22 years was associated with a lower incidence of recipient clinical pregnancy (P = 0.004) and live birth (P = 0.001) after the first embryo transfer versus donor age 23-29 years. CONCLUSIONS: Donor age and AMH are independent predictors of oocyte yield. Raised recipient BMI and history of miscarriages reduce cumulative live birth rates, which may be increased by selecting donors aged 23-29 years, instead of younger donors.

Increased obstetric and neonatal risks in artificial cycles for frozen embryo transfers?

RESEARCH QUESTION: What are the obstetric and neonatal risks for women conceiving via frozen-thawed embryo transfer (FET) during a modified natural cycle compared with an artificial cycle method. DESIGN: A follow-up study to the ANTARCTICA randomized controlled trial (RCT) (NTR 1586) conducted in the Netherlands, which showed that modified natural cycle FET (NC-FET) was non-inferior to artificial cycle FET (AC-FET) in terms of live birth rates. The current study collected data on obstetric and neonatal outcomes of 98 women who had a singleton live birth. The main outcome was birthweight; additional outcomes included hypertensive disorder of pregnancy, premature birth, gestational diabetes, obstetric haemorrhage and neonatal outcomes including Apgar scores and admission to the neonatal ward or the neonatal intensive care unit and congenital anomalies. RESULTS: Data from 82 out of 98 women were analysed according to the per protocol principle. There was no significant difference in the birthweights of children born between groups (mean difference -124 g [-363 g to 114 g]; P = 0.30). Women who conceived by modified NC-FET have a decreased risk of hypertensive disorders of pregnancy compared with AC-FET (relative risk 0.27; 95% CI 0.08-0.94; P = 0.031). Other outcomes, such as rates of premature birth, gestational diabetes or obstetric haemorrhage and neonatal outcomes, were not significantly different. CONCLUSIONS: The interpretation is that modified NC-FET is the preferred treatment in women with ovulatory cycles undergoing FET when the increased risk of obstetrical complications and potential neonatal complications in AC-FET are considered.

Vitrification and the demise of fresh treatment cycles in ART.

The advent of vitrification has transformed the therapeutic landscape in assisted reproductive technology. Clear evidence for this is provided by the dramatic rise in the number of frozen embryo transfer (FET) cycles being carried out annually. In this review, we examine the reasons that underlie this trend and the current evidence that points to the place FET cycles will come to inhabit in the future. Safety issues have been central to the narrative around the clinical application of vitrification and, as the evidence base grows, the risk benefit balance will become clearer for different patient groups. These will include recipients of donor eggs, as in some centres the use of cryopreserved donor eggs now exceeds that of fresh oocytes. Efficient cryopreservation techniques have also affected international transport of gametes and embryos, increasing international access. The profound changes that vitrification has created promises to fulfil a prediction made by this journal's founding Editor, Bob Edwards, that embryo and cryopreservation would solve many of the challenges presented by assisted reproductive technology.

Cumulative live birth rates following insemination with donor spermatozoa in single women, same-sex couples and heterosexual patients.

RESEARCH QUESTION: What is the cumulative live birth rate (LBR) following donor intrauterine insemination (IUI-D) treatment in a large, retrospective, single-centre cohort of single women, same-sex couples and heterosexual patients? DESIGN: Outcomes from 8922 treatments performed in 3333 consecutive women (45% single, 43% from same-sex and 12% from heterosexual couples) were analysed in a 13-year retrospective study from a private, HFEA-regulated UK centre between January 2004 and December 2016. RESULTS: A total of 795 live births resulted in an overall delivery rate of 8.9% per cycle, including 24 (3%) twins. Age-specific crude and expected cumulative LBR calculated in four age groups (<35, 35-37, 38-39 and 40-42 years) were 29, 23, 21, 12% and 66, 49, 54, 28%, respectively. A plateau was reached after six cycles, beyond which there were few additional live births. There was no significant difference in cumulative LBR between single women and same-sex couples. In a multivariate analysis, female age (adjusted odds ratio [aOR] 0.92; 95% confidence interval [CI] 0.90-0.93; P < 0.0001), previous live birth following IUI-D (aOR 2.15; 95% CI 1.69-2.73; P < 0.0001) and mild stimulation (aOR 1.27; 95% CI 1.09-1.48; P = 0.02) had a significant effect on outcome, but relationship status or cycle rank did not. CONCLUSIONS: These results indicate there is little benefit performing more than six cycles of IUI-D in all women up to 40 years old, including those from same-sex relationships, while only three attempts seem reasonable in those aged 40-42 years. These results do not reflect current clinical guidelines in the UK. The authors found that consecutive IUI cycles, especially with mild stimulation, were an efficient treatment in all indications.

Effective support following recurrent pregnancy loss: a randomized controlled feasibility and acceptability study.

RESEARCH QUESTION: Is it feasible to perform a future definitive trial to determine the effectiveness of the positive reappraisal coping intervention (PRCI) in improving the psychological well-being of women with recurrent pregnancy loss (RPL) during the early stages of a new pregnancy? DESIGN: This mixed method study aimed to establish the feasibility of conducting a multicentre randomized controlled trial (RCT) to definitively test the effects of the PRCI on the psychological well-being of women with RPL. Participants (n = 75) were recruited to the study and at the point of a positive pregnancy test, 47 were randomized into two study groups. The intervention group received the PRCI and weekly questionnaire assessment (Hospital Anxiety and Depression Scale and Weekly Record Keeping Form [WRK]) to monitor psychological well-being; the control group received the same questionnaires. Nested within the RCT was a qualitative process evaluation (QPE) exploring participants' subjective experience of study methods and the intervention. The study was conducted over a two-year period between 2014 and 2016. RESULTS: This study successfully gathered knowledge about the feasibility aspects of conducting a future multicentre definitive study to determine the effects of the PRCI on the psychological well-being of women with RPL. Participants were receptive to its use and the intervention appeared to convey benefits with no apparent downside. CONCLUSIONS: The study concluded that a definitive RCT of the PRCI is possible and that the model of care already has the potential to be made more widely available as a safe, low-cost, convenient and easily deliverable intervention to provide much-needed support to a vulnerable patient population.

Assessing endometrial receptivity after recurrent implantation failure: a prospective controlled cohort study.

RESEARCH QUESTION: What is the prevalence of disrupted markers of endometrial function among women experiencing recurrent implantation failure (RIF), and does the prevalence differ from a control cohort? DESIGN: Prospective controlled cohort study. In total, 86 women with a history of RIF and 37 women starting their first fertility treatment were recruited for this study. Endometrial and blood profiling were carried out in a hormone-substituted cycle using oestradiol and progesterone. Endometrial biopsies were analysed by histology, immune cell profiling, and the endometrial receptivity array (ERA®) test (Igenomix, Valencia, Spain). The vaginal microbiome was analysed using a NGS-based technology (ArtPRED, Amsterdam, the Netherlands). Blood tests included oestradiol, progesterone, prolactin, thyroid-stimulating hormone, vitamin D and anti-phospholipid antibody levels. RESULTS: Patients who had experienced RIF produced a range of test abnormalities. Compared with controls, women with RIF had a higher prevalence of chronic endometritis (24% versus 6%), a lower vitamin D level and a borderline lower progesterone level. Women who had experienced RIF had a more favourable vaginal microbiome compared with controls. Although the RIF cohort was older than the controls (mean age 33.8 years versus 30.2 years), no differences between the groups were observed in immune cell profiling and the ERA test. CONCLUSION: These data demonstrate that a single test or treatment for the endometrial factor in RIF is unlikely to be clinically effective. Diagnosing the endometrium in women with RIF permits targeted rather than blind interventions. Relative vitamin D deficiency, lower mid-luteal progesterone and chronic endometritis are ready targets for treatment. Understanding the role and treatment of an unfavourable vaginal microbiome in RIF needs further investigation.

Testing the endometrium: is there enough evidence to justify clinical use?

PURPOSE OF REVIEW: Embryo implantation remains the limiting factor in assisted reproduction outcomes. To date research has mainly focused on improving embryo quality, numbers and selection as the route to improve treatment results. However, with success rates plateauing, interest in the possibility of modulating the endometrial factor is increasing, and a number of biomarkers are now available that offer the possibility of assessing endometrial function. RECENT FINDINGS: In this review, we review recent evidence for the efficacy of a number of these biomarkers, with emphasis on those that aim to enable improvement in embryo/endometrial developmental synchrony endometrium and that offer an assessment of the degree of immune activation of the endometrium. The emerging field of reproductive tract microbiome analysis is also considered. Finally, nascent biomarkers of materno-foetal dialogue, including noncoding RNAs, microvesicles and endometrial glycans are discussed. SUMMARY: Tests of potential clinical value are emerging, but further validation studies are required. The usage of innovative endometrial biomarkers provides the possibility of targeted therapies rather than the blind empirical approaches to face embryo implantation failure. It also enables the possibility of randomized controlled trials of interventions targeting the individual cause rather empirical treatments of undiagnosed recurrent implantation failure.

Dydrogesterone: pharmacological profile and mechanism of action as luteal phase support in assisted reproduction.

The pharmacological and physiological profiles of progestogens used for luteal phase support during assisted reproductive technology are likely to be important in guiding clinical choice towards the most appropriate treatment option. Various micronized progesterone formulations with differing pharmacological profiles have been investigated for several purposes. Dydrogesterone, a stereoisomer of progesterone, is available in an oral form with high oral bioavailability; it has been used to treat a variety of conditions related to progesterone deficiency since the 1960s and has recently been approved for luteal phase support as part of an assisted reproductive technology treatment. The primary objective of this review is to critically analyse the clinical implications of the pharmacological and physiological properties of dydrogesterone for its uses in luteal phase support and in early pregnancy.

Study protocol: E-freeze - freezing of embryos in assisted conception: a randomised controlled trial evaluating the clinical and cost effectiveness of a policy of freezing embryos followed by thawed frozen embryo transfer compared with a policy of fresh embryo transfer, in women undergoing in vitro fertilisation.

BACKGROUND: Infertility affects one in seven couples; many of these need in vitro fertilisation (IVF). IVF involves external hormones to stimulate a woman's ovaries to produce eggs which are harvested surgically. Embryos, created in the laboratory by mixing eggs with sperm, are grown in culture for a few days before being replaced within the uterus (fresh embryo transfer). Spare embryos are usually frozen with a view to transfer at a later point in time - especially if the initial fresh transfer does not result in a pregnancy. Despite improvements in technology, IVF success rates remain low with an overall live birth rate of 25-30% per treatment. Additionally, there are concerns about health outcomes for mothers and babies conceived through IVF, particularly after fresh embryo transfer, including maternal ovarian hyperstimulation syndrome (OHSS) and preterm delivery. It is believed that high levels of hormones during ovarian stimulation could create a relatively hostile environment for embryo implantation whilst increasing the risk of OHSS. It has been suggested that freezing all embryos with the intention of thawing and replacing them within the uterus at a later stage (thawed frozen embryo transfer) instead of fresh embryo transfer, may lead to improved pregnancy rates and fewer complications. We aim to compare the clinical and cost effectiveness of fresh and thawed frozen embryo transfer, with the primary aim of identifying any difference in the chance of having a healthy baby. METHODS: E-Freeze is a pragmatic, multicentre two-arm parallel group randomised controlled trial where women aged ≥18 and < 42 years, with at least three good quality embryos are randomly allocated to receive either a fresh or thawed frozen embryo transfer. The primary outcome is a healthy baby, defined as a term, singleton, live birth with appropriate weight for gestation. Cost effectiveness will be calculated from a healthcare and societal perspective. DISCUSSION: E-Freeze will determine the relative benefits of fresh and thawed frozen embryo transfer in terms of improving the chance of having a healthy baby. The results of this pragmatic study have the potential to be directly transferred to clinical practice. TRIAL REGISTRATION: ISRCTN registry: ISRCTN61225414 . Date assigned 29/12/2015.

The growth of assisted reproductive treatment-conceived children from birth to 5 years: a national cohort study.

BACKGROUND: Birth weight and early child growth are important predictors of long-term cardiometabolic disease risk, in line with the Developmental Origins of Health and Disease hypothesis. As human assisted reproductive technologies (ARTs) occur during the sensitive periconceptional window of development, it has recently become a matter of urgency to investigate risk in ART-conceived children. METHODS: We have conducted the first large-scale, national cohort study of early growth in ART children from birth to school age, linking the register of ART, held by the UK's Human Fertilisation and Embryology Authority, to Scottish maternity and child health databases. RESULTS: In this study of 5200 ART and 20,800 naturally conceived (NC) control children, linear regression analysis revealed the birthweight of babies born from fresh embryo transfer cycles is 93.7 g [95% CI (76.6, 110.6)g] less than NC controls, whereas babies born from frozen embryo transfer (FET) cycles are 57.5 g [95% CI (30.7, 86.5)g] heavier. Fresh ART babies grew faster from birth (by 7.2 g/week) but remained lighter (by 171 g), at 6-8 weeks, than NC babies and 133 g smaller than FET babies; FET and NC babies were similar. Length and occipital-frontal circumference followed the same pattern. By school entry (4-7 years), weight, length and BMI in boys and girls conceived by fresh ART and FET were similar to those in NC children. CONCLUSIONS: ART babies born from fresh embryo transfer grow more slowly in utero and in the first few weeks of life, but then show postnatal catch up growth by school age, compared to NC and FET babies. As low birth weight and postnatal catch-up are independent risk factors for cardiometabolic disease over the life-course, we suggest that further studies in this area are now warranted.

Influence of endometrial thickness on pregnancy rates in modified natural cycle frozen-thawed embryo transfer.

INTRODUCTION: Pregnancy after frozen-thawed embryo transfer (FET) is a multifactorial process. Although embryo quality is a key factor in determining pregnancy, other factors, including maternal determinants, are also considered to be predictive. Even though an association between endometrial thickness measured by transvaginal ultrasound and pregnancy rates has been reported in patients undergoing various assisted reproductive technology treatments, whether endometrial thickness predicts achieving pregnancy after natural cycle FET (NC-FET) remains unclear. MATERIAL AND METHODS: In this cohort study, 463 patients allocated to the modified NC-FET (mNC-FET) arm of a previously published randomized controlled trial were included. Monitoring in mNC-FET cycles consisted of regular ultrasound scans, measuring both dominant follicle and endometrial thickness. When the dominant follicle reached a size of 16-20 mm, an injection of human chorionic gonadotrophin was administered and embryo thawing and transfer planned. No minimal endometrial thickness was defined below which transfer was to be deferred. The primary endpoint was ongoing pregnancy rate. RESULTS: Overall, the ongoing pregnancy rate per started FET cycle was 12.5%. Multivariate regression analyses showed that embryo quality was the only significant predictor for ongoing pregnancy. Mean endometrial thickness did not differ between patients achieving ongoing pregnancy and those who did not (9.0 vs. 8.8 mm, p = 0.4). Comparable results were obtained with regard to clinical pregnancy, live birth and miscarriage rates. The area under the receiver operator curve was 0.5, indicating little discriminatory value of endometrial thickness. CONCLUSIONS: Given that endometrial thickness was not found to be predictive of pregnancy after mNC-FET, cancellation based on endometrial thickness alone may not be justified.