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

Anxiety in couples undergoing IVF: evidence from E-Freeze randomised controlled trial

STUDY QUESTION

What are the risk factors and impacts of anxiety in women and men in heterosexual couples undergoing IVF as part of a randomised trial, with a delay in embryo transfer in one arm?

SUMMARY ANSWER

Duration of infertility, ethnicity, and male partner's anxiety levels were associated with women's anxiety at the start of treatment, while initial anxiety score, partner's anxiety score at embryo transfer, ethnicity, and clinic location were associated with women's anxiety levels at embryo transfer; although women undergoing IVF were more anxious than their partners for slightly different reasons, their self-reported state anxiety was not associated with achieving clinical pregnancy, nor with switching from delayed frozen embryo transfer to fresh embryo transfer in an IVF trial.

WHAT IS KNOWN ALREADY

Use of IVF treatment continues to rise and patients undergoing IVF are anxious. Participating in a randomised controlled trial (RCT) with uncertainty of arm randomisation might increase their anxiety, while a delay in treatment may add further to anxiety.

STUDY DESIGN SIZE DURATION

A mixed methods study was conducted using data from the multi-centre E-Freeze RCT cohort conducted across 13 clinics in the UK from 2016 to 2019. A regression analysis on anxiety scores of couples undergoing the IVF trial and a qualitative analysis of participant questionnaires were performed.

PARTICIPANTS/MATERIALS SETTING METHODS

Six hundred and four couples participating in the E-Freeze trial, who had at least one useable State-Trait Anxiety Inventory (STAI) State Anxiety subscale (STAI-S) standardised self-report questionnaire for at least one of the partners, were included in the study. STAI-S scores were measured at consent for trial (T1) and again at embryo transfer (T2). Linear and log-binomial regression were used to explore the association between characteristics and STAI-S scores, and the associations between STAI-S scores and non-compliance and clinical pregnancy, respectively. Responses to the open text question were qualitatively analysed inductively using content analysis.

MAIN RESULTS AND THE ROLE OF CHANCE

Women's STAI-S scores at T1 (consent) were associated with their ethnicity, duration of infertility, and their male partner's STAI-S score at T1. Women's STAI-S scores at T2 (embryo transfer) were associated with their ethnicity, location of fertility clinic, their STAI-S score at consent, and their male partner's STAI-S score at embryo transfer. The adjusted coefficient (95% CI) for women's STAI-S scores at T2 was -4.75 (-7.29, -2.20, P < 0.001) for ethnic minority versus White, -2.87 (-4.85, -0.89, P = 0.005) for Scotland versus England, 0.47 (0.37, 0.56, P < 0.001) for each point increase in their own score at T1, and 0.30 (0.21, 0.40, P < 0.001) for each point increase in their male partner's score at T2. On average, women had higher STAI-S scores than men at both time points, and a larger increase of scores between the two time points. However, women's STAI-S scores were not associated with either non-compliance with trial allocation in the 'freeze-all' trial arm, or with chances of pregnancy. Both partners, but particularly women, described feeling anxious about the outcome of IVF, with women carrying the added worry of believing that feeling stressed might itself affect the outcome. Participants highlighted the important role of support from staff in helping them to manage their anxiety.

LIMITATIONS REASONS FOR CAUTION

Data were not available on education level or social support, which might influence anxiety scores. Men's baseline characteristics were not collected.

WIDER IMPLICATIONS OF THE FINDINGS

Identifying couples at increased risk of emotional distress may be improved by using standardised anxiety measures at the start of the fertility treatment. Women can be reassured that their self-reported state anxiety does not affect their chances of achieving clinical pregnancy through IVF, and this may help to reduce anxiety levels. The psychological wellbeing and experiences of couples undergoing IVF could be supported by patient-centred care: making information about the whole process of treatment and choices available to both partners in accessible formats; ensuring interactions with staff are kind and supportive; and acknowledging and addressing the different concerns of women undergoing IVF and their partners.

STUDY FUNDING/COMPETING INTERESTS

This study was an NIHR HTA (National Institute for Health and Care Research Health Technology Assessment) funded study. There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

ISRCTN registry: ISRCTN61225414.

Antibiotic cured chronic endometritis remains a risk factor for early pregnancy loss in the subsequent frozen euploid embryo transfer

RESEARCH QUESTION

Do patients with antibiotic-cured chronic endometritis (CCE) have a comparable pregnancy outcome to those with non-chronic endometritis (NCE) in the subsequent frozen embryo transfer (FET) cycle?

DESIGN

A retrospective cohort analysis included 833 patients in their first FET cycles with single euploid embryo transfer. Chronic endometritis (≥5 CD138+ plasma cells per high-power field [CD138+/HPF]) was treated with standard antibiotic therapy. Patients were classified into two groups: the NCE group (n = 611, <5 CD138+/HPF) and the CCE group (n = 222, ≥5 CD138+/HPF and cured after antibiotic treatment). Pregnancy outcomes were compared. NCE group was divided into subgroup 1 (CD138+/HPF = 0) and subgroup 2 (CD138+/HPF = 1-4) for further analysis.

RESULTS

The rate of early pregnancy loss (EPL), incorporating all losses before 10 weeks' gestation, was significantly higher in the CCE group than the NCE group (21.2% versus 14.2%, P = 0.016), and the difference was statistically significant (adjusted odds ratio [AOR] 1.68, 95% confidence interval [CI] 1.11-2.55). No significant differences were observed between the two groups with regard to other pregnancy outcomes. In the subgroup analysis, the EPL rate and biochemical pregnancy rate were significantly higher in subgroup 2 than subgroup 1 (17.2% versus 9.4%, AOR 2.21, 95% CI 1.30-3.74; 12.2% versus 6.9%, AOR 2.01, 95% CI 1.09-3.68).

CONCLUSIONS

Chronic endometritis cured by standard antibiotic therapy remains a risk factor for EPL in FET cycles, although no differences were found in live birth rates between patients with CCE or with NCE.

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.

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.

Endometrial scratch to increase live birth rates in women undergoing first-time in vitro fertilisation: RCT and systematic review

BACKGROUND

In vitro fertilisation is a widely used reproductive technique that can be undertaken with or without intracytoplasmic sperm injection. The endometrial scratch procedure is an in vitro fertilisation 'add-on' that is sometimes provided prior to the first in vitro fertilisation cycle, but there is a lack of evidence to support its use.

OBJECTIVES

(1) To assess the clinical effectiveness, safety and cost-effectiveness of endometrial scratch compared with treatment as usual in women undergoing their first in vitro fertilisation cycle (the 'Endometrial Scratch Trial') and (2) to undertake a systematic review to combine the results of the Endometrial Scratch Trial with those of previous trials in which endometrial scratch was provided prior to the first in vitro fertilisation cycle.

DESIGN

A pragmatic, multicentre, superiority, open-label, parallel-group, individually randomised controlled trial. Participants were randomised (1 : 1) via a web-based system to receive endometrial scratch or treatment as usual using stratified block randomisation. The systematic review involved searching electronic databases (undertaken in January 2020) and clinicaltrials.gov (undertaken in September 2020) for relevant trials.

SETTING

Sixteen UK fertility units.

PARTICIPANTS

Women aged 18-37 years, inclusive, undergoing their first in vitro fertilisation cycle. The exclusion criteria included severe endometriosis, body mass index ≥ 35 kg/m² and previous trauma to the endometrium.

INTERVENTIONS

Endometrial scratch was undertaken in the mid-luteal phase of the menstrual cycle prior to in vitro fertilisation, and involved inserting a pipelle into the cavity of the uterus and rotating and withdrawing it three or four times. The endometrial scratch group then received usual in vitro fertilisation treatment. The treatment-as-usual group received usual in vitro fertilisation only.

MAIN OUTCOME MEASURES

The primary outcome was live birth after completion of 24 weeks' gestation within 10.5 months of egg collection. Secondary outcomes included implantation, pregnancy, ectopic pregnancy, miscarriage, pain and tolerability of the procedure, adverse events and treatment costs.

RESULTS

One thousand and forty-eight (30.3%) women were randomised to treatment as usual (n = 525) or endometrial scratch (n = 523) and were followed up between July 2016 and October 2019 and included in the intention-to-treat analysis. In the endometrial scratch group, 453 (86.6%) women received the endometrial scratch procedure. A total of 494 (94.1%) women in the treatment-as-usual group and 497 (95.0%) women in the endometrial scratch group underwent in vitro fertilisation. The live birth rate was 37.1% (195/525) in the treatment-as-usual group and 38.6% (202/523) in the endometrial scratch group: an unadjusted absolute difference of 1.5% (95% confidence interval -4.4% to 7.4%; p = 0.621). There were no statistically significant differences in secondary outcomes. Safety events were comparable across groups. No neonatal deaths were recorded. The cost per successful live birth was £11.90 per woman (95% confidence interval -£134 to £127). The pooled results of this trial and of eight similar trials found no evidence of a significant effect of endometrial scratch in increasing live birth rate (odds ratio 1.03, 95% confidence interval 0.87 to 1.22).

LIMITATIONS

A sham endometrial scratch procedure was not undertaken, but it is unlikely that doing so would have influenced the results, as objective fertility outcomes were used. A total of 9.2% of women randomised to receive endometrial scratch did not undergo the procedure, which may have slightly diluted the treatment effect.

CONCLUSIONS

We found no evidence to support the theory that performing endometrial scratch in the mid-luteal phase in women undergoing their first in vitro fertilisation cycle significantly improves live birth rate, although the procedure was well tolerated and safe. We recommend that endometrial scratch is not undertaken in this population.

TRIAL REGISTRATION

This trial is registered as ISRCTN23800982.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 10. See the NIHR Journals Library website for further project information.

The Current Role of Induced Endometrial Trauma (Endometrial Scratch) in Women Undergoing Infertility Treatment

Induced endometrial trauma, otherwise known as endometrial scratch is a simple technique that has been rapidly adopted into clinical practice, mainly for women having IVF treatment, in an attempt to increase pregnancy rates. The introduction of endometrial scratch followed early reports of improved clinical pregnancy rates in women with repetitive implantation failure after having the procedure and follows on from evidence from animal models in the early 20^th century suggesting that mechanical trauma to the endometrium can induce decidual changes. Due to the ease and low cost of the procedure, it has been rapidly adopted as an add-on to fertility treatments, in many cases where evidence is still lacking. Despite the initial publication of a large number of studies that demonstrated encouraging improvements in pregnancy rates in women who underwent this procedure, these studies were mainly limited by the small sample sizes and heterogeneity of their study populations, leading to limited validity of the evidence provided by these studies. More recently, three large randomized controlled studies have been published that paint a different picture regarding the value of this procedure. This article explores the evolution of the evidence and the current state of endometrial scratch as an adjuvant therapy for women undergoing IVF treatment.

Does the freeze-all strategy improve the cumulative live birth rate and the time to become pregnant in IVF cycles?

PURPOSE

The freeze-all strategy is widely used for ovarian hyperstimulation syndrome (OHSS) prevention. Indeed, it increases live birth rates among high responders and prevents preterm birth and small for gestational age. Why should not we extend it to all?

METHODS

A retrospective and monocentric study was conducted between January 2008 and January 2018 comparing the cumulative live birth rates (CLBR) between patients having undergone FAS and a control group using fresh embryo transfer (FET) and having at least one frozen embryo available. Analyses were made for the entire cohort (population 1) and for different subgroups according to confounding factors selected by a logistic regression (population 3), and to the BELRAP (Belgian Register for Assisted Procreation) criteria (population 2).

RESULTS

2216 patients were divided into two groups: Freeze all (FA), 233 patients and control (C), 1983 patients. The CLBR was 50.2% vs 58.1% P = 0.021 for population 1 and 53.2% vs 63.3% P = 0.023 for population 2, including 124 cases and 1241 controls. The CLBR stayed in favour of the C group: 70.1% vs 55.9% P = 0.03 even when confounding variables were excluded (FA and C group, respectively, 109 and 770 patients). The median time to become pregnant was equally in favour of the C group with a median of 5 days against 61 days.

CONCLUSION

CLBR is significantly lower in the FA group compared to the C group with a longer time to become pregnant. Nevertheless, the CLBR in the FA group remains superior to that observed in previous studies.

Fresh versus frozen embryo transfers in assisted reproduction

BACKGROUND

In vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) treatments conventionally consist of a fresh embryo transfer, possibly followed by one or more cryopreserved embryo transfers in subsequent cycles. An alternative option is to freeze all suitable embryos and transfer cryopreserved embryos in subsequent cycles only, which is known as the 'freeze all' strategy. This is the first update of the Cochrane Review on this comparison.

OBJECTIVES

To evaluate the effectiveness and safety of the freeze all strategy compared to the conventional IVF/ICSI strategy in women undergoing assisted reproductive technology.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group Trials Register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, and two registers of ongoing trials from inception until 23 September 2020 for relevant studies, checked references of publications found, and contacted study authors to obtain additional data.

SELECTION CRITERIA

Two review authors (TZ and MZ) independently selected studies for inclusion, assessed risk of bias, and extracted study data. We included randomised controlled trials comparing a 'freeze all' strategy with a conventional IVF/ICSI strategy including a fresh embryo transfer in women undergoing IVF or ICSI treatment.

DATA COLLECTION AND ANALYSIS

The primary outcomes were cumulative live birth rate and ovarian hyperstimulation syndrome (OHSS). Secondary outcomes included effectiveness outcomes (including ongoing pregnancy rate and clinical pregnancy rate), time to pregnancy and obstetric, perinatal and neonatal outcomes.

MAIN RESULTS

We included 15 studies in the systematic review and eight studies with a total of 4712 women in the meta-analysis. The overall evidence was of moderate to low quality. We graded all the outcomes and downgraded due to serious risk of bias, serious imprecision and serious unexplained heterogeneity. Risk of bias was associated with unclear blinding of investigators for preliminary outcomes of the study during the interim analysis, unit of analysis error, and absence of adequate study termination rules. There was an absence of high-quality evidence according to GRADE assessments for our primary outcomes, which is reflected in the cautious language below. There is probably little or no difference in cumulative live birth rate between the 'freeze all' strategy and the conventional IVF/ICSI strategy (odds ratio (OR) 1.08, 95% CI 0.95 to 1.22; I2 = 0%; 8 RCTs, 4712 women; moderate-quality evidence). This suggests that for a cumulative live birth rate of 58% following the conventional strategy, the cumulative live birth rate following the 'freeze all' strategy would be between 57% and 63%. Women might develop less OHSS after the 'freeze all' strategy compared to the conventional IVF/ICSI strategy (OR 0.26, 95% CI 0.17 to 0.39; I2 = 0%; 6 RCTs, 4478 women; low-quality evidence). These data suggest that for an OHSS rate of 3% following the conventional strategy, the rate following the 'freeze all' strategy would be 1%. There is probably little or no difference between the two strategies in the cumulative ongoing pregnancy rate (OR 0.95, 95% CI 0.75 to 1.19; I2 = 31%; 4 RCTs, 1245 women; moderate-quality evidence).  We could not analyse time to pregnancy; by design, time to pregnancy is shorter in the conventional strategy than in the 'freeze all' strategy when the cumulative live birth rate is comparable, as embryo transfer is delayed in a 'freeze all' strategy. We are uncertain whether the two strategies differ in cumulative miscarriage rate because the evidence is very low quality (Peto OR 1.06, 95% CI 0.72 to 1.55; I2 = 55%; 2 RCTs, 986 women; very low-quality evidence) and cumulative multiple-pregnancy rate (Peto OR 0.88, 95% CI 0.61 to 1.25; I2 = 63%; 2 RCTs, 986 women; very low-quality evidence). The risk of hypertensive disorders of pregnancy (Peto OR 2.15, 95% CI 1.42 to 3.25; I2 = 29%; 3 RCTs, 3940 women; low-quality evidence), having a large-for-gestational-age baby (Peto OR 1.96, 95% CI 1.51 to 2.55; I2 = 0%; 3 RCTs, 3940 women; low-quality evidence) and a higher birth weight of the children born (mean difference (MD) 127 g, 95% CI 77.1 to 177.8; I2 = 0%; 5 RCTs, 1607 singletons; moderate-quality evidence) may be increased following the 'freeze all' strategy. We are uncertain whether the two strategies differ in the risk of having a small-for-gestational-age baby because the evidence is low quality (Peto OR 0.82, 95% CI 0.65 to 1.05; I2 = 64%; 3 RCTs, 3940 women; low-quality evidence).

AUTHORS' CONCLUSIONS

We found moderate-quality evidence showing that one strategy is probably not superior to the other in terms of cumulative live birth rate and ongoing pregnancy rate. The risk of OHSS may be decreased in the 'freeze all' strategy. Based on the results of the included studies, we could not analyse time to pregnancy. It is likely to be shorter using a conventional IVF/ICSI strategy with fresh embryo transfer in the case of similar cumulative live birth rate, as embryo transfer is delayed in a 'freeze all' strategy. The risk of maternal hypertensive disorders of pregnancy, of having a large-for-gestational-age baby and a higher birth weight of the children born may be increased following the 'freeze all' strategy. We are uncertain if 'freeze all' strategy reduces the risk of miscarriage, multiple pregnancy rate or having a small-for-gestational-age baby compared to conventional IVF/ICSI.

Pregnancy outcomes of the first thawing cycle in "freeze-all" strategy of infertility patients with fever during oocyte recruitment: a matched-pair study

Background:

It is currently unknown whether patients with a fever after controlled ovulation during egg retrieval could increase the risk of pelvic infection or not, and fever itself may affect endometrial receptivity or embryo quality with poor pregnancy outcomes. The aim of this study was to analyze the outcomes of patients with fever during oocyte retrieval after the first frozen-thawed embryo transfer (FET) cycle.

Methods:

This was a 1:3 retrospective paired study matched for age. In this study, 58 infertility patients (Group 1) had a fever during the control ovulation, and the time of the oocyte retrieval was within 72 hours, they underwent ovum pick up and whole embryo freezing (“freeze-all” strategy). The control subjects (Group 2) are 174 patients matched for age who underwent whole embryo freezing for other reasons. The baseline characteristics, clinical data of ovarian stimulation, and outcomes, such as the clinical pregnancy rate, ongoing clinical pregnancy rate were compared between the two groups in the subsequent FET cycle.

Results:

All patients had no pelvic inflammatory disease after oocyte retrieval. Anti-Mullerian hormone (AMH) levels (4.2 vs. 2.2, P <0.001) were higher in group 2, and the number of oocytes retrieved, and fertilization rate were lower in group 1 (P < 0.001), but the endometrial thickness, the number of embryo transfers, and the type of luteal support supplementation were similar between the two groups. Regarding pregnancy outcomes in the subsequent FET cycle, the implantation rate, clinical pregnancy rate, early spontaneous rate, ectopic pregnancy rate, and ongoing pregnancy rate were all not significantly different. Further regression analyses showed that the clinical pregnancy rate and ongoing pregnancy rate were also not significantly different.

Conclusions:

Transvaginal ultrasound-guided follicular puncture for oocyte retrieval is a safe and minimally invasive method for patients with fever. Moreover, the fever had almost no effect on embryo quality.

E-Freeze - 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: a statistical analysis plan

Background

The E-Freeze trial is a multi-centre randomised controlled trial of fresh versus frozen embryo transfer for women undergoing in vitro fertilisation. This paper describes the statistical analysis plan for the E-Freeze trial.

Methods and design

E-Freeze is a two-arm parallel-group, multi-centre, individually randomised controlled trial to determine if a policy of freezing embryos, followed by thawed frozen embryo transfer, results in a higher healthy baby rate when compared with the current policy of transferring fresh embryos. Couples undergoing their first, second or third cycle of in vitro fertilisation at fertility centres in the UK were randomised to either fresh or frozen embryo transfer. The primary outcome is a healthy baby, defined as a live singleton baby born at term with an appropriate weight for gestation. This paper describes the statistical analysis plan for the trial, including the analysis principles, definitions of outcomes, methods for primary analysis, pre-specified subgroup analysis and sensitivity analysis. This plan was finalised prior to completion of recruitment to the trial.

Trial registration

ISRCTN registry: ISRCTN61225414. Registered on 29 December 2015.

The Future of Cryopreservation in Assisted Reproductive Technologies

Societal changes and the increasing desire and opportunity to preserve fertility have increased the demand for effective assisted reproductive technologies (ART) and have increased the range of scenarios in which ART is now used. In recent years, the "freeze-all" strategy of cryopreserving all oocytes or good quality embryos produced in an IVF cycle to transfer later-at a time that is more appropriate for reasons of medical need, efficacy, or desirability-has emerged as an accepted and valuable alternative to fresh embryo transfer. Indeed, improvements in cryopreservation techniques (vitrification) and the development of more efficient ovarian stimulation protocols have facilitated a dramatic increase in the practice of elective frozen embryo transfer (eFET). Alongside these advances, debate continues about whether eFET should be a standard treatment option available to the whole IVF population or if it is important to identify patient subgroups who are most likely to benefit from such an approach. Achieving successful outcomes in ART, whether by fresh or frozen embryo transfer, is influenced by a wide range of factors. As well as the efficiency of IVF and embryo transfer protocols and techniques, factors affecting implantation include maternal aging, sperm quality, the vaginal and endometrial microbiome, and peri-implantation levels of serum progesterone. The safety of eFET, both during ART cycles and on longer-term obstetric and neonatal outcomes, is also an important consideration. In this review, we explore the benefits and risks of freeze-all strategies in different scenarios. We review available evidence on the outcomes achieved with elective cryopreservation strategies and practices and how these compare with more traditional IVF cycles with fresh embryo transfers, both in the general IVF population and in subgroups of special interest. In addition, we consider how to optimize and individualize "freeze-all" procedures to achieve successful reproductive outcomes.

The Role of hCG Triggering Progesterone Levels: A Real-World Retrospective Cohort Study of More Than 8000 IVF/ICSI Cycles

Objective: To assess the association between serum ovulation trigger progesterone (P) levels and the outcome of in vitro fertilization cycles. Design Setting: Real world single-center retrospective cohort study. Patient Intervention(s): All fresh cleavage and blastocyst-stage embryo transfers (ETs) performed from January 2012 to December 2016. Main outcome Measure(s): The impact of premature high serum P levels cycles in terms of clinical pregnancy rates (CPRs) and live birth rates (LBRs). Results: 8,034 ETs were performed: 7,597 cleavage-stage transfers and 437 blastocyst transfers. Serum P levels demonstrated to be inversely related to CPR (OR 0.72, p < 0.001) and LBR (OR 0.73, p < 0.001). The progressive decrease of LBR and CPR started when P levels were >1 ng/ml in a good prognosis cleavage ET subgroup, whereas in patients with worse prognosis only for P ≥ 1.75 ng/ml. In the blastocyst ET subgroup, the negative effect of P elevation was reported only if P was >1.75 ng/ml. CPR (OR 0.71 (0.62-0.80), p < 0.001) and LBR (OR 0.73 (0.63-0.84), p < 0.001) in thawed cycles resulted statistically significantly higher than in fresh cycles in the cleavage-stage subgroup. In the blastocyst group, no significant difference resulted between thawed and fresh cycles, independently of P levels [CPR OR 0. 37 (0.49-1.09), p = 0.123; LBR OR 0.71 (0.46-1.10), p = 0.126]. Conclusion: High P levels decrease CPR as well as LBR in both cleavage and blastocyst ET. In the cleavage group, for P levels below 1.75 ng/ml, our data suggest the possibility to wait until day 5 for ET, and if P level is ≥1.75 ng/ml, it should be considered to freeze all embryos and postpone the ET. Clinical Trial Registration: ClinicalTrials.gov, ID: NCT04253470.

[Economic studies of in vitro fertilization and embryo transfer]

In vitro fertilization and embryo transplantation (IVF-ET) technology is one of the main treatments for infertility. But IVF-ET is expensive and has not be covered by health insurance in most developing countries. Therefore, how to obtain the maximum success rate with the minimum cost is a common concern of clinicians and patients. At present, the economic studies on IVF-ET mainly focus on different ovulation stimulating drugs, different ovulation stimulating protocols, different transplantation methods and the number of transplants. But the process of IVF-ET is complex, the relevant methods of economic study are diverse, and there are no unified standard for outcome indicators, so there is no unified conclusion for more economical and effective protocol by now. Therefore, to analyze the economic studies of IVF-ET, and to explore appropriate evaluation methods and cost-effective protocols will be helpful for reasonable allocation of medical resources and guidance of clinical selection. It would provide policy reference to include the costs of IVF-ET treatment in health insurance in the future.

Fresh versus frozen embryo transfers in assisted reproduction

BACKGROUND

In general, in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) implies a single fresh and one or more frozen-thawed embryo transfers. Alternatively, the 'freeze-all' strategy implies transfer of frozen-thawed embryos only, with no fresh embryo transfers. In practice, both strategies can vary technically including differences in freezing techniques and timing of transfer of cryopreservation, that is vitrification versus slow freezing, freezing of two pro-nucleate (2pn) versus cleavage-stage embryos versus blastocysts, and transfer of cleavage-stage embryos versus blastocysts.In the freeze-all strategy, embryo transfers are disengaged from ovarian stimulation in the initial treatment cycle. This could avoid a negative effect of ovarian hyperstimulation on the endometrium and thereby improve embryo implantation. It could also reduce the risk of ovarian hyperstimulation syndrome (OHSS) in the ovarian stimulation cycle by avoiding a pregnancy.We compared the benefits and risks of the two treatment strategies.

OBJECTIVES

To evaluate the effectiveness and safety of the freeze-all strategy compared to the conventional IVF/ICSI strategy in women undergoing assisted reproductive technology.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group Trials Register, the Cochrane Central Register of Studies (CRSO), MEDLINE, Embase, PsycINFO, CINAHL, and two registers of ongoing trials in November 2016 together with reference checking and contact with study authors and experts in the field to identify additional studies.

SELECTION CRITERIA

We included randomised clinical trials comparing a freeze-all strategy with a conventional IVF/ICSI strategy which includes fresh transfer of embryos in women undergoing IVF or ICSI treatment.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. The primary review outcomes were cumulative live birth and OHSS. Secondary outcomes included other adverse effects (miscarriage rate).

MAIN RESULTS

We included four randomised clinical trials analysing a total of 1892 women comparing a freeze-all strategy with a conventional IVF/ICSI strategy. The evidence was of moderate to low quality due to serious risk of bias and (for some outcomes) serious imprecision. Risk of bias was associated with unclear blinding of investigators for preliminary outcomes of the study, unit of analysis error, and absence of adequate study termination rules.There was no clear evidence of a difference in cumulative live birth rate between the freeze-all strategy and the conventional IVF/ICSI strategy (odds ratio (OR) 1.09, 95% confidence interval (CI) 0.91 to 1.31; 4 trials; 1892 women; I² = 0%; moderate-quality evidence). This suggests that if the cumulative live birth rate is 58% following a conventional IVF/ICSI strategy, the rate following a freeze-all strategy would be between 56% and 65%.The prevalence of OHSS was lower after the freeze-all strategy compared to the conventional IVF/ICSI strategy (OR 0.24, 95% CI 0.15 to 0.38; 2 trials; 1633 women; I² = 0%; low-quality evidence). This suggests that if the OHSS rate is 7% following a conventional IVF/ICSI strategy, the rate following a freeze-all strategy would be between 1% and 3%.The freeze-all strategy was associated with fewer miscarriages (OR 0.67, 95% CI 0.52 to 0.86; 4 trials; 1892 women; I² = 0%; low-quality evidence) and a higher rate of pregnancy complications (OR 1.44, 95% CI 1.08 to 1.92; 2 trials; 1633 women; low-quality evidence). There was no difference in multiple pregnancies per woman after the first transfer (OR 1.11, 95% CI 0.85 to 1.44; 2 trials; 1630 women; low-quality evidence), and no data were reported for time to pregnancy.

AUTHORS' CONCLUSIONS

We found moderate-quality evidence showing that one strategy is not superior to the other in terms of cumulative live birth rates. Time to pregnancy was not reported, but it can be assumed to be shorter using a conventional IVF/ICSI strategy in the case of similar cumulative live birth rates, as embryo transfer is delayed in a freeze-all strategy. Low-quality evidence suggests that not performing a fresh transfer lowers the OHSS risk for women at risk of OHSS.