Establishment of a relationship between blastomere geometry and YAP localisation during compaction.

Precise patterning within the three-dimensional context of tissues, organs and embryos implies that cells can sense their relative position. During preimplantation development, outside and inside cells rely on apicobasal polarity and the Hippo pathway to choose their fate. Despite recent findings suggesting that mechanosensing might be central to this process, the relationship between blastomere geometry (i.e. shape and position) and the Hippo pathway effector YAP remains unknown. We used a highly quantitative approach to analyse information on the geometry and YAP localisation of individual blastomeres of mouse and human embryos. We identified the proportion of exposed cell surface area as most closely correlating with the nuclear localisation of YAP. To test this relationship, we developed several hydrogel-based approaches to alter blastomere geometry in cultured embryos. Unbiased clustering analyses of blastomeres from such embryos revealed that this relationship emerged during compaction. Our results therefore pinpoint the time during early embryogenesis when cells acquire the ability to sense changes in geometry and provide a new framework for how cells might integrate signals from different membrane domains to assess their relative position within the embryo.

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.

A randomised controlled trial to assess the clinical effectiveness and safety of the endometrial scratch procedure prior to first-time IVF, with or without ICSI.

STUDY QUESTION: What is the clinical-effectiveness and safety of the endometrial scratch (ES) procedure compared to no ES, prior to usual first time in vitro fertilisation (IVF) treatment? SUMMARY ANSWER: ES was safe but did not improve pregnancy outcomes when performed in the mid-luteal phase prior to the first IVF cycle, with or without intracytoplasmic sperm injection (ICSI). WHAT IS KNOWN ALREADY: ES is an 'add-on' treatment that is available to women undergoing a first cycle of IVF, with or without ICSI, despite a lack of evidence to support its use. STUDY DESIGN, SIZE, DURATION: This pragmatic, superiority, open-label, multi-centre, parallel-group randomised controlled trial involving 1048 women assessed the clinical effectiveness and safety of the ES procedure prior to first time IVF, with or without ICSI, between July 2016 and October 2019. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants aged 18-37 years undergoing their first cycle of IVF, with or without ICSI, were recruited from 16 UK fertility clinics and randomised (1:1) by a web-based system with restricted access rights that concealed allocation. Stratified block randomisation was used to allocate participants to TAU or ES in the mid-luteal phase followed by usual IVF with or without ICSI treatment. The primary outcome was live birth after completing 24 weeks gestation within 10.5 months of egg collection. MAIN RESULTS AND THE ROLE OF CHANCE: In total, 1048 women randomised to TAU (n = 525) and ES (n = 523) were available for intention to treat analysis. In the ES group, 453 (86.6%) received the ES procedure. IVF, with or without ICSI, was received in 494 (94.1%) and 497 (95.0%) of ES and TAU participants respectively. Live birth rate was 37.1% (195/525) in the TAU and 38.6% (202/523) in the ES: an unadjusted absolute difference of 1.5% (95% CI -4.4% to 7.4%, P = 0.621). There were no statistical differences in secondary outcomes. Adverse events were comparable across groups. LIMITATIONS, REASONS FOR CAUTION: A sham ES procedure was not undertaken in the control group, however, we do not believe this would have influenced the results as objective fertility outcomes were used. WIDER IMPLICATIONS OF THE FINDINGS: This is the largest trial that is adequately powered to assess the impact of ES on women undergoing their first cycle of IVF. ES was safe, but did not significantly improve pregnancy outcomes when performed in the mid-luteal phase prior to the first IVF or ICSI cycle. We recommend that ES is not undertaken in this population. STUDY FUNDING/COMPETING INTEREST(S): Funded by the National Institute of Health Research. Stephen Walters is an National Institute for Health Research (NIHR) Senior Investigator (2018 to present) and was a member of the following during the project: National Institute for Health Research (NIHR) Health Technology Assessment (HTA) Clinical Trials and Evaluation Committee (2011-2017), NIHR HTA Commissioning Strategy Group (2012 to 2017); NIHR Programme Grants for Applied Research Committee (2020 to present); NIHR Pre doctoral Fellowship Committee (2019 to present). Dr. Martins da Silva reports grants from AstraZeneca, during the conduct of the study; and is Associate editor of Human Reproduction and Editorial Board member of Reproduction and Fertility. Dr. Bhide reports grants from Bart's Charity and grants and non-financial support from Pharmasure Pharmaceuticals outside the submitted work. TRIAL REGISTRATION NUMBER: ISRCTN number: ISRCTN23800982. TRIAL REGISTRATION DATE: 31 May 2016. DATE OF FIRST PATIENT'S ENROLMENT: 04 July 2016.

Short versus extended progesterone supplementation for luteal phase support in fresh IVF cycles: a systematic review and meta-analysis.

This review and meta-analysis aim to assess the effect of prolonged progesterone support on pregnancy outcomes in women undergoing fresh embryo transfer after IVF/intracytoplasmic sperm injection (ICSI). Two independent authors searched Embase, MEDLINE and grey literature from inception to January 2019 for randomized controlled trials (RCT) of prolonged progesterone support versus early cessation. Risk of bias was assessed. Outcome measures were live birth, miscarriage and ongoing pregnancy rate. The study was registered with PROSPERO (CRD42018088605). Seven trials involving 1627 participants were included: three reported live birth rate (672/830), seven the miscarriage rate (178/1627) and seven the ongoing pregnancy rate (1351/1627). Clinical outcomes were similar between early progesterone cessation versus progesterone continuation: live birth rate (risk ratio [RR] 0.94, 95% confidence interval [CI] 0.88-1.00), miscarriage rate (RR 0.91, 95% CI 0.69-1.20) and ongoing pregnancy rate (RR 0.98, 95% CI 0.91-1.05). Ongoing pregnancy rates were similar when analyses were restricted to those with cessation of progesterone on the day of a positive human chorionic gonadotrophin (RR 0.93, 95% CI 0.83-1.06). This meta-analysis suggests that prolonged progesterone support may be unnecessary after fresh embryo transfer. Further larger RCT would be useful to corroborate and lead to standardized duration of progesterone luteal phase support across IVF/ICSI centres.

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.

Systematic review of the clinical efficacy of vaginal progesterone for luteal phase support in assisted reproductive technology cycles.

Vaginal progesterone via capsule, gel or tablet is the most common route for luteal phase support (LPS) in Europe. Although there is a wealth of data comparing products used at other stages of assisted reproductive technology cycles, there is a lack of systematically identified evidence comparing the wide range of vaginal progesterone products. This systematic review queried the MEDLINE, Embase and Cochrane Library databases on 30 June 2016 to identify head-to-head randomized controlled trials (RCTs) comparing the efficacy or safety of vaginal progesterone preparations (Crinone, Cyclogest, Lutigest or Utrogestan Vaginal) for LPS in assisted reproductive technology cycles. Of 1914 results, 18 RCTs were included. No significant difference in clinical pregnancy rate was identified in comparisons of Utrogestan Vaginal with Crinone. Utrogestan Vaginal and Lutigest were non-inferior to Crinone in ongoing pregnancy rate comparisons. Differences in patient-reported perineal irritation with Crinone and Lutigest were not significantly different to Cyclogest. In studies comparing varying timing or dosage of Utrogestan Vaginal or Crinone, no significant differences were observed. These results suggest Crinone, Cyclogest, Lutigest and Utrogestan Vaginal represent equally safe and effective choices of vaginal progesterone for LPS in assisted reproductive technology cycles. Future quantitative analyses could provide further support for these findings.

Modulating mitochondrial quality in disease transmission: towards enabling mitochondrial DNA disease carriers to have healthy children.

One in 400 people has a maternally inherited mutation in mtDNA potentially causing incurable disease. In so-called heteroplasmic disease, mutant and normal mtDNA co-exist in the cells of carrier women. Disease severity depends on the proportion of inherited abnormal mtDNA molecules. Families who have had a child die of severe, maternally inherited mtDNA disease need reliable information on the risk of recurrence in future pregnancies. However, prenatal diagnosis and even estimates of risk are fraught with uncertainty because of the complex and stochastic dynamics of heteroplasmy. These complications include an mtDNA bottleneck, whereby hard-to-predict fluctuations in the proportions of mutant and normal mtDNA may arise between generations. In 'mitochondrial replacement therapy' (MRT), damaged mitochondria are replaced with healthy ones in early human development, using nuclear transfer. We are developing non-invasive alternatives, notably activating autophagy, a cellular quality control mechanism, in which damaged cellular components are engulfed by autophagosomes. This approach could be used in combination with MRT or with the regular management, pre-implantation genetic diagnosis (PGD). Mathematical theory, supported by recent experiments, suggests that this strategy may be fruitful in controlling heteroplasmy. Using mice that are transgenic for fluorescent LC3 (the hallmark of autophagy) we quantified autophagosomes in cleavage stage embryos. We confirmed that the autophagosome count peaks in four-cell embryos and this correlates with a drop in the mtDNA content of the whole embryo. This suggests removal by mitophagy (mitochondria-specific autophagy). We suggest that modulating heteroplasmy by activating mitophagy may be a useful complement to mitochondrial replacement therapy.

Tead4 and Tfap2c generate bipotency and a bistable switch in totipotent embryos to promote robust lineage diversification.

The mouse and human embryo gradually loses totipotency before diversifying into the inner cell mass (ICM, future organism) and trophectoderm (TE, future placenta). The transcription factors TFAP2C and TEAD4 with activated RHOA accelerate embryo polarization. Here we show that these factors also accelerate the loss of totipotency. TFAP2C and TEAD4 paradoxically promote and inhibit Hippo signaling before lineage diversification: they drive expression of multiple Hippo regulators while also promoting apical domain formation, which inactivates Hippo. Each factor activates TE specifiers in bipotent cells, while TFAP2C also activates specifiers of the ICM fate. Asymmetric segregation of the apical domain reconciles the opposing regulation of Hippo signaling into Hippo OFF and the TE fate, or Hippo ON and the ICM fate. We propose that the bistable switch established by TFAP2C and TEAD4 is exploited to trigger robust lineage diversification in the developing embryo.

Optimising the management of patients with infertility.

The main causes of infertility are female factor (anovulation, tubal damage, endometriosis and ovarian failure), male factor (low or absent numbers of motile sperm in the ejaculate, and erectile dysfunction), or unexplained infertility. More than 80% of couples will conceive within one year if the woman is aged under 40 and they have regular sexual intercourse. Of those who fail to conceive in the first year, around half will do so in the second year, giving a cumulative pregnancy rate > 90%. A woman of reproductive age who has not conceived after a year of regular sexual intercourse, and has no known cause of infertility, should be offered referral for further clinical assessment and investigation with her partner. Women who have a BMI > or = 30 are likely to take longer to conceive. Those with a BMI < 19 who have irregular or absent menstruation should be advised that putting on weight is likely to improve their chance of conception. The best test of ovulation is an appropriately timed mid-luteal serum progesterone level. Women with irregular or absent menstrual cycles should be offered a blood test to measure serum gonadotrophin levels (FSH and LH). Women with no known comorbidities should be screened for tubal occlusion. Those who are thought to have comorbidities should be offered laparoscopy and dye testing.

Viability assessment for artificial gametes: the need for biomarkers of functional competency.

Assisted reproductive technology (ART) has resulted in more than 5 million births worldwide. However, mainstream ART techniques are not always successful for an estimated 30% of infertile patients in whom gametes are nonviable. Most patients would clearly prefer genetic parenthood, currently possible only via the use of donated gametes or, in future, via the clinical use of artificial gametes (AGs) incorporating parental DNA. Despite much recent progress in the derivation of AGs, significant obstacles remain. Although it is possible to create artificial cells exhibiting some of the molecular and physiological traits of human gametes, they do not yet exhibit the same level of functionality as their in vivo counterparts. Most current effort pays scant attention to confirmation of molecular integrity and clinical applicability of AGs. Here we discuss the various clinical parameters used to assess gamete and embryo viability and discuss markers of gamete function that may be used within future studies attempting to derive AGs. The use of AGs may prove controversial to some members of the general public, and, as such, there is significant need for an appropriate ethical and legal framework governing the clinical use of such cells. However, provided these issues can be successfully overcome, it is highly likely that AGs will represent powerful biological tools for reproductive science, a valuable training resource for embryologists and for potential use in the clinical treatment of human infertility.

Motile sperm organelle morphology evaluation-selected globozoospermic human sperm with an acrosomal bud exhibits novel patterns and higher levels of phospholipase C zeta.

STUDY QUESTION: Does motile sperm organelle morphology examination (MSOME) affect levels and localization patterns of the oocyte activation factor phospholipase C zeta (PLCζ) in globozoospermic sperm with and without an acrosomal bud? SUMMARY ANSWER: MSOME identified round-headed globozoospermic sperm with increased levels of PLCζ relative to sperm from the same sample that did not undergo MSOME, and identified novel patterns of PLCζ localization in sperm exhibiting an acrosomal bud. WHAT IS KNOWN ALREADY: Absence or reduction in the level of PLCζ in the sperm head, abnormal localization patterning, or defective functional ability as a result of PLCζ gene mutation, have been linked to certain types of human male factor infertility in which oocyte activation is deficient. It has been determined that a subpopulation of sperm (1%) from a patient exhibiting 100% globozoospermia presented with an acrosome bud upon MSOME. A cycle of intracytoplasmic morphologically selected sperm injection, carried out with sperm exhibiting an acrosomal bud led to pregnancy and birth of a healthy baby boy, without the use of assisted oocyte activation (AOA). STUDY DESIGN, SIZE, DURATION: Immunofluorescent analysis of PLCζ in globozoospermic sperm from three patients, before and after MSOME. PARTICIPANTS/MATERIALS, SETTING, METHODS: Quantitative immunofluorescence was used to investigate PLCζ levels and localization patterns in individual sperm (n = 1 patient) identified by MSOME and isolated by micromanipulation, and presenting with and without the acrosomal bud. A secondary aim was to investigate levels and localization patterns of PLCζ in sperm before and after MSOME from two other globozoospermic men. MAIN RESULTS AND THE ROLE OF CHANCE: Non-globozoospermic control sperm exhibited characteristic localization patterns of PLCζ immunofluorescence. Completely round-headed globozoospermic sperm from patients 1-3 were either devoid of PLCζ immunofluorescence, or exhibited an abnormal, punctate, pattern of PLCζ localization. PLCζ immunofluorescence in sperm exhibiting an acrosomal bud was observed in the midpiece with varying fluorescent intensity and was detected in 28.5% of such sperm. The majority of sperm with an acrosomal bud (43.0%) exhibited punctate patterns of PLCζ localization within the sperm head. A further 28.5% of sperm exhibited PLCζ in both the head and the midpiece. Total levels of PLCζ, and the proportions of sperm exhibiting PLCζ immunoreactivity, showed significant variance (P ≤ 0.05) amongst control [45.8 arbitrary units (a.u.) and 95.7%, respectively], non-MSOME-selected (25.9 a.u. and 46.1%, respectively) and MSOME-selected globozoospermic sperm (33.4 a.u. and 65.0%, respectively). Total levels of PLCζ immunofluorescence, and proportions of sperm exhibiting PLCζ immunoreactivity, in control sperm was significantly higher (P≤ 0.05) compared with non-MSOME-selected sperm, but not significantly different from MSOME-selected sperm. LIMITATIONS, REASONS FOR CAUTION: The low numbers of sperm analysed may not be ideal for conclusive statistical analysis. Evaluation of the effects of MSOME on morphologically normal sperm would confirm conclusions. WIDER IMPLICATIONS OF THE FINDINGS: The present findings provide hope for the future treatment of globozoospermia without the need for AOA, and provide further evidence for the clinical application of PLCζ as a therapeutic and prognostic tool. STUDY FUNDING/COMPETING INTEREST(S): The research described herein was funded by the Nuffield Department of Obstetrics and Gynaecology, University of Oxford. The authors report no conflict of interest.

A UK-wide cross-sectional survey of practice exploring current trends in endometrial preparation for frozen-thawed embryo replacement.

In the United Kingdom, between 2012 and 2017 the annual number of frozen-thawed embryo replacement (FER) cycles doubled, while fresh cycles declined. With FER now accounting for 34% of IVF cycles, the aim of this UK-wide survey of IVF clinics was to determine current trends in the management of FER. A senior clinician in each of the 84 UK IVF clinics was asked to complete an online survey between September 2018 and February 2019 focussing on their clinic's first-line protocols for FER. Sixty-five clinics (77%) responded, accounting for approximately 24,419 FER cycles annually. In ovulatory women, 69% of clinics favour medicated, 26% natural cycle and 5% modified natural cycle FER. In medicated FER, 61% of clinics undertake blastocyst transfer on the sixth day of progesterone administration, 21% on the fifth, 13% on the seventh, 3% on the fourth and 2% on the third. The preferred route of progesterone in medicated FER is vaginal, favoured by 82% of clinics. For pituitary suppression, 55% of clinics favour GnRH-agonist, 11% GnRH-antagonist and 34% oestrogen-only. In natural cycle FER, 31% always, 44% sometimes and 25% never give supplementary luteal support. In summary, the results illustrate wide variation in practice and highlight key research priorities.

Antigen unmasking does not improve the visualization of phospholipase C zeta in human spermatozoa.

Phospholipase C zeta (PLCζ) is a sperm-specific protein that triggers oocyte activation. The analysis of PLCζ expression in human spermatozoa can be used as a diagnostic marker for oocyte activation deficiency. Our laboratory has previously optimized a standard "in-house" assay to determine PLCζ expression in human spermatozoa. However, one study has suggested that an antigen unmasking method (AUM) would be more efficient in visualizing PLCζ in human sperm. This study aimed to compare our established assay and AUM (involving HCl, acidic Tyrode's solution [AT], and heat). The mean relative fluorescence (RF) intensity of PLCζ in frozen-thawed spermatozoa from fourteen fertile donors stained with the in-house method was significantly higher than three other AUM groups (in-house [mean ± standard error of mean]: 18.87 ± 2.39 arbitrary units [a.u.] vs non-AUM: 11.44 ± 1.61 a.u., AT-AUM: 12.38 ± 1.89 a.u., and HCl-AUM: 12.51 ± 2.16 a.u., P < 0.05, one-way analysis of variance). The mean RF intensity of PLCζ in AT- and HCl-treated spermatozoa from 12 infertile males was not significantly different from that of the non-AUM group. However, the in-house method resulted in the highest RF intensity (12.11 ± 1.36 a.u., P < 0.01). Furthermore, specificity testing of antibody-antigen binding indicated that the in-house method showed more specific binding than spermatozoa treated by the AUM. In conclusion, our in-house method showed superior visualization and reliability than the AUM, thus supporting the continued use of our in-house assay for clinical research screening.

Characterisation of peri-implantation endometrial Treg and identification of an altered phenotype in recurrent pregnancy loss.

Recurrent Pregnancy Loss (RPL) affects 2-4% of couples, and with increasing numbers of pregnancy losses the risk of miscarrying a euploid pregnancy is increased, suggesting RPL is a pathology distinct from sporadic miscarriage that is due largely to lethal embryonic aneuploidy. There are a number of conditions associated with RPL including unspecified "immune" pathologies; one of the strongest candidates for dysregulation remains T regulatory cells as depletion in the very early stages of pregnancy in mice leads to pregnancy loss. Human endometrial Treg and conventional CD4T cells were isolated during the peri-implantation period of the menstrual cycle in normal women. We identified an endometrial Treg transcriptomic signature and validated an enhanced regulatory phenotype compared to peripheral blood Treg. Parous women had an altered endometrial Treg transcriptome compared to nulliparity, indicating acquired immune memory of pregnancy within the Treg population, by comparison endometrial conventional CD4T cells were not altered. We compared primary and secondary RPL to nulliparous or parous controls respectively. Both RPL subgroups displayed differentially expressed Treg gene transcriptomes compared to controls. We found increased cell surface S1PR1 and decreased TIGIT protein expression by Treg in primary RPL, confirming the presence of altered Treg in the peri-implantation RPL endometrium.

ASPP2 maintains the integrity of mechanically stressed pseudostratified epithelia during morphogenesis.

During development, pseudostratified epithelia undergo large scale morphogenetic events associated with increased mechanical stress. Using a variety of genetic and imaging approaches, we uncover that in the mouse E6.5 epiblast, where apical tension is highest, ASPP2 safeguards tissue integrity. It achieves this by preventing the most apical daughter cells from delaminating apically following division events. In this context, ASPP2 maintains the integrity and organisation of the filamentous actin cytoskeleton at apical junctions. ASPP2 is also essential during gastrulation in the primitive streak, in somites and in the head fold region, suggesting that it is required across a wide range of pseudostratified epithelia during morphogenetic events that are accompanied by intense tissue remodelling. Finally, our study also suggests that the interaction between ASPP2 and PP1 is essential to the tumour suppressor function of ASPP2, which may be particularly relevant in the context of tissues that are subject to increased mechanical stress.

Transfer of thawed frozen embryo versus fresh embryo to improve the healthy baby rate in women undergoing IVF: the E-Freeze RCT.

BACKGROUND: Freezing all embryos, followed by thawing and transferring them into the uterine cavity at a later stage (freeze-all), instead of fresh-embryo transfer may lead to improved pregnancy rates and fewer complications during in vitro fertilisation and pregnancies resulting from it. OBJECTIVE: We aimed to evaluate if a policy of freeze-all results in a higher healthy baby rate than the current policy of transferring fresh embryos. DESIGN: This was a pragmatic, multicentre, two-arm, parallel-group, non-blinded, randomised controlled trial. SETTING: Eighteen in vitro fertilisation clinics across the UK participated from February 2016 to April 2019. PARTICIPANTS: Couples undergoing their first, second or third cycle of in vitro fertilisation treatment in which the female partner was aged < 42 years. INTERVENTIONS: If at least three good-quality embryos were present on day 3 of embryo development, couples were randomly allocated to either freeze-all (intervention) or fresh-embryo transfer (control). OUTCOMES: The primary outcome was a healthy baby, defined as a live, singleton baby born at term, with an appropriate weight for their gestation. Secondary outcomes included ovarian hyperstimulation, live birth and clinical pregnancy rates, complications of pregnancy and childbirth, health economic outcome, and State-Trait Anxiety Inventory scores. RESULTS: A total of 1578 couples were consented and 619 couples were randomised. Most non-randomisations were because of the non-availability of at least three good-quality embryos (n = 476). Of the couples randomised, 117 (19%) did not adhere to the allocated intervention. The rate of non-adherence was higher in the freeze-all arm, with the leading reason being patient choice. The intention-to-treat analysis showed a healthy baby rate of 20.3% in the freeze-all arm and 24.4% in the fresh-embryo transfer arm (risk ratio 0.84, 95% confidence interval 0.62 to 1.15). Similar results were obtained using complier-average causal effect analysis (risk ratio 0.77, 95% confidence interval 0.44 to 1.10), per-protocol analysis (risk ratio 0.87, 95% confidence interval 0.59 to 1.26) and as-treated analysis (risk ratio 0.91, 95% confidence interval 0.64 to 1.29). The risk of ovarian hyperstimulation was 3.6% in the freeze-all arm and 8.1% in the fresh-embryo transfer arm (risk ratio 0.44, 99% confidence interval 0.15 to 1.30). There were no statistically significant differences between the freeze-all and the fresh-embryo transfer arms in the live birth rates (28.3% vs. 34.3%; risk ratio 0.83, 99% confidence interval 0.65 to 1.06) and clinical pregnancy rates (33.9% vs. 40.1%; risk ratio 0.85, 99% confidence interval 0.65 to 1.11). There was no statistically significant difference in anxiety scores for male participants (mean difference 0.1, 99% confidence interval -2.4 to 2.6) and female participants (mean difference 0.0, 99% confidence interval -2.2 to 2.2) between the arms. The economic analysis showed that freeze-all had a low probability of being cost-effective in terms of the incremental cost per healthy baby and incremental cost per live birth. LIMITATIONS: We were unable to reach the original planned sample size of 1086 and the rate of non-adherence to the allocated intervention was much higher than expected. CONCLUSION: When efficacy, safety and costs are considered, freeze-all is not better than fresh-embryo transfer. TRIAL REGISTRATION: This trial is registered as ISRCTN61225414. FUNDING: This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 25. See the NIHR Journals Library website for further project information.

During in vitro fertilisation, eggs and sperm are mixed in a laboratory to create embryos. An embryo is placed in the womb 2­5 days later (fresh-embryo transfer) and the remaining embryos are frozen for future use. Initial research suggested that freezing all embryos followed by thawing and replacing them a few weeks later could improve treatment safety and success. Although these data were promising, the data came from small studies and were not enough to change practice and policy. We conducted a large, multicentre, clinical trial to evaluate the two strategies: fresh-embryo transfer compared with later transfer of frozen embryos. We also compared the costs of both strategies during in vitro fertilisation treatment, pregnancy and delivery. This study was conducted across 18 clinics in the UK from 2016 to 2019, and 619 couples participated. Couples were allocated to one of two strategies: immediate fresh-embryo transfer or freezing of all embryos followed later by transfer of frozen embryo. The study's aim was to find out which type of embryo transfer gave participants a higher chance of having a healthy baby. We found that freezing all embryos followed by frozen-embryo transfer did not lead to a higher chance of having a healthy baby. There were no differences between strategies in the number of live births, the miscarriage rate or the number of pregnancy complications. Fresh-embryo transfer was less costly from both a health-care and a patient perspective. A routine strategy of freezing all embryos is not justified given that there was no increase in success rates but there were extra costs and delays to embryo transfer.

Do women with ovaries of polycystic morphology without any other features of PCOS benefit from short-term metformin co-treatment during IVF? A double-blind, placebo-controlled, randomized trial.

BACKGROUND: Women with ovaries of polycystic morphology (PCO), without any other features of polycystic ovary syndrome (PCOS), respond similarly to women with PCOS when stimulated with exogenous gonadotrophins, and both groups share various endocrinological disturbances underlying their pathology. In women with PCOS, metformin co-treatment during IVF has been shown to increase pregnancy rates and reduce the risk of ovarian hyperstimulation syndrome (OHSS). The aim of this study was to investigate whether metformin co-treatment before and during IVF can also increase the live birth rate (LBR) and lower severe OHSS rates for women with PCO, but no other manifestations of PCOS. METHODS: This study was a double-blind, multi-centre, randomized, placebo-controlled trial. The study population included 134 women with ovulatory PCO (and no evidence of clinical or biochemical hyperandrogenism) undergoing IVF treatment at three tertiary referral IVF units. The primary outcome was LBR. RESULTS: In total, 134 women were randomized, 69 to metformin and 65 to placebo. There were no statistically significant differences between the two groups in baseline characteristics. With regard to IVF outcome, no significant improvements were found in the metformin group when compared with the placebo group. In particular, there was no difference between the groups in rates of live birth [metformin n = 27 (39.1%), placebo n = 30 (46.2), (95% confidence interval 0.38, 1.49, odds ratio = 0.75)], clinical pregnancy [metformin n = 29 (42.0%), placebo n = 33 (50.8%)] or severe OHSS [metformin n = 6 (8.7%), placebo n = 5 (7.7%)]. CONCLUSIONS: There appears to be no benefit in metformin co-treatment before and during IVF in women with PCO without any other features of PCOS. Clinical Trials.gov: NCT01046032.

B Cell Subset Analysis and Gene Expression Characterization in Mid-Luteal Endometrium.

The human endometrium is the innermost mucosal membrane of the uterus and is the first point of contact for an implanting blastocyst. A wide variety of immune cells are found amongst the endometrial epithelial layers and stromal cells which both provide host immune responses against pathogens and also assist with placentation and pregnancy establishment, however, B cells have not been characterized, despite being a vital player in both adaptive and mucosal immunity. Through analysis of mid-luteal endometrial biopsies, we find 1-5% of endometrial immune cells are B cells, the majority were naïve or memory B cells, with few plasma cells. Compared with circulating B cells, endometrial B cells had an activated phenotype, with increased expression of CD69, HLA-DR, CD74, and CD83, and IL-10 production capacities. PD1+CXCR5+ICOS+ T follicular helper-like cells and FAS+IgD-BCL6+ germinal center B cells were also present in the endometrium, which may indicate that endometrial B cells are playing an active role through germinal center reactions in the human endometrial environment.

Clinical application of sequencing-based methods for parallel preimplantation genetic testing for mitochondrial DNA disease and aneuploidy.

OBJECTIVE: To validate and apply a strategy permitting parallel preimplantation genetic testing (PGT) for mitochondrial DNA (mtDNA) disease and aneuploidy (PGT-A). DESIGN: Preclinical test validation and case reports. SETTING: Fertility centers. Diagnostics laboratory. PATIENTS: Four patients at risk of transmitting mtDNA disease caused by m.8993T>G (Patients A and B), m.10191T>G (Patient C), and m.3243A>G (Patient D). Patients A, B, and C had affected children. Patients A and D displayed somatic heteroplasmy for mtDNA mutations. INTERVENTIONS: Embryo biopsy, genetic testing, and uterine transfer of embryos predicted to be euploid and mutation-free. MAIN OUTCOME MEASURES: Test accuracy, treatment outcomes, and mutation segregation. RESULTS: Accuracy of mtDNA mutation quantification was confirmed. The test was compatible with PGT-A, and half of the embryos tested were shown to be aneuploid (16/33). Mutations were detected in approximately 40% of embryo biopsies from Patients A and D (10/24) but in none from Patients B and C (n = 29). Patients B and C had healthy children following PGT and natural conception, respectively. The m.8993T>G mutation displayed skewed segregation, whereas m.3243A>G mutation levels were relatively low and potentially impacted embryo development. CONCLUSIONS: Considering the high aneuploidy rate, strategies providing a combination of PGT for mtDNA disease and aneuploidy may be advantageous compared with approaches that consider only mtDNA. Heteroplasmic women had a higher incidence of affected embryos than those with undetectable somatic mutant mtDNA but were still able to produce mutation-free embryos. While not conclusive, the results are consistent with the existence of mutation-specific segregation mechanisms occurring during oogenesis and possibly embryogenesis.