Trade-off between double cleavage-stage embryos transfer and single blastocyst-stage embryo transfer in patients with few good quality embryos in antagonist cycles: a retrospective study using a propensity score matching analysis.

This study aimed to compare the per OPU clinical outcomes for transfer of Day 3 double cleavage-stage embryos (DET) and Day 5 single blastocyst-stage (SBT) in patients with five or fewer good quality embryos on day 3 per occyte pick-up cycle (OPU) in antagonist cycles with consideration of blastocyst formation failure. This was a retrospective, observational cohort study of 2,116 cases of OPU treated with antagonist protocol in the affiliated Chenggong Hospital of Xiamen University between January 2013 and December 2020. DET was performed in 1,811cycles and SBT was performed in 305 cycles. The DET group was matched to the SBT group by propensity score (PS) matching according to multiple maternal baseline covariates. After PS matching, there were 303 ET cycles in each group. The primary outcomes were the cumulative live birth rate (CLBR), cumulative multiple pregnancy rate(CMPR)per OPU and the number of ET to achieve live birth per OPU. Secondary outcomes were the percentage of clinical pregnancy(CPR), live birth rate(LBR), multiple pregnancy rate(MPR). Following PS mating, the CLBR was slightly higher (48.8% versus 40.3% ; P = 0.041) and the CMPR was significantly higher in the DET group compared to SBT group(44.2% versus 7.9%, P < 0.001). The CPR, LBR and MPR per fresh transfer were higher in DET group compared to SBT group(50.2% versus 28.7%; 41.3% versus 21.5%;29.6% versus 0%, P < 0.001). The number of ET to achieve live birth per OPU in SBT group was obiviously more than in DET group(1.48 ± 0.578 versus 1.22 ± 0.557 ,P < 0.001). With a marginal difference cumulative live birth rate, the lower live birth rate per fresh transfer and higher number of ET per OPU in the SBT group suggested that it might take longer time to achieve a live birth with single blastocyst strategy. A trade-off decision should be made between efficiency and safety.

Han Y ，Deng X ，Cai J ，Peng W ，Duan C ，Huang K ... -  《BMC Pregnancy and Childbirth》

Number of embryos for transfer following in vitro fertilisation or intra-cytoplasmic sperm injection.

Transfer of more than one embryo during in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) increases multiple pregnancy rates resulting in an increased risk of maternal and perinatal morbidity. Elective single embryo transfer offers a means of minimising this risk, but this potential gain needs to be balanced against the possibility of jeopardising the overall live birth rate (LBR). To evaluate the effectiveness and safety of different policies for the number of embryos transferred in infertile couples undergoing assisted reproductive technology cycles. We searched the Cochrane Gynaecology and Fertility Group specialised register of controlled trials, CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform from inception to March 2020. We handsearched reference lists of articles and relevant conference proceedings. We also communicated with experts in the field regarding any additional studies. We included randomised controlled trials (RCTs) comparing different policies for the number of embryos transferred following IVF or ICSI in infertile women. Studies of fresh or frozen and thawed transfer of one to four embryos at cleavage or blastocyst stage were eligible. Two review authors independently extracted data and assessed trial eligibility and risk of bias. The primary outcomes were LBR and multiple pregnancy rate. The secondary outcomes were clinical pregnancy and miscarriage rates. We analysed data using risk ratios (RR), Peto odds ratio (Peto OR) and a fixed effect model. We included 17 RCTs in the review (2505 women). The main limitation was inadequate reporting of study methods and moderate to high risk of performance bias due to lack of blinding. A majority of the studies had low numbers of participants. None of the trials compared repeated single embryo transfer (SET) with multiple embryo transfer. Reported results of multiple embryo transfer below refer to double embryo transfer. Repeated single embryo transfer versus multiple embryo transfer in a single cycle Repeated SET was compared with double embryo transfer (DET) in four studies of cleavage-stage transfer. In these studies the SET group received either two cycles of fresh SET (one study) or one cycle of fresh SET followed by one frozen SET (three studies). The cumulative live birth rate after repeated SET may be little or no different from the rate after one cycle of DET (RR 0.95, 95% CI (confidence interval) 0.82 to 1.10; I² = 0%; 4 studies, 985 participants; low-quality evidence). This suggests that for a woman with a 42% chance of live birth following a single cycle of DET, the repeated SET would yield pregnancy rates between 34% and 46%. The multiple pregnancy rate associated with repeated SET is probably reduced compared to a single cycle of DET (Peto OR 0.13, 95% CI 0.08 to 0.21; I² = 0%; 4 studies, 985 participants; moderate-quality evidence). This suggests that for a woman with a 13% risk of multiple pregnancy following a single cycle of DET, the risk following repeated SET would be between 0% and 3%. The clinical pregnancy rate (RR 0.99, 95% CI 0.87 to 1.12; I² = 47%; 3 studies, 943 participants; low-quality evidence) after repeated SET may be little or no different from the rate after one cycle of DET. There may be little or no difference in the miscarriage rate between the two groups. Single versus multiple embryo transfer in a single cycle A single cycle of SET was compared with a single cycle of DET in 13 studies, 11 comparing cleavage-stage transfers and three comparing blastocyst-stage transfers.One study reported both cleavage and blastocyst stage transfers. Low-quality evidence suggests that the live birth rate per woman may be reduced in women who have SET in comparison with those who have DET (RR 0.67, 95% CI 0.59 to 0.75; I² = 0%; 12 studies, 1904 participants; low-quality evidence). Thus, for a woman with a 46% chance of live birth following a single cycle of DET, the chance following a single cycle of SET would be between 27% and 35%. The multiple pregnancy rate per woman is probably lower in those who have SET than those who have DET (Peto OR 0.16, 95% CI 0.12 to 0.22; I² = 0%; 13 studies, 1952 participants; moderate-quality evidence). This suggests that for a woman with a 15% risk of multiple pregnancy following a single cycle of DET, the risk following a single cycle of SET would be between 2% and 4%. Low-quality evidence suggests that the clinical pregnancy rate may be lower in women who have SET than in those who have DET (RR 0.70, 95% CI 0.64 to 0.77; I² = 0%; 10 studies, 1860 participants; low-quality evidence). There may be little or no difference in the miscarriage rate between the two groups. Although DET achieves higher live birth and clinical pregnancy rates per fresh cycle, the evidence suggests that the difference in effectiveness may be substantially offset when elective SET is followed by a further transfer of a single embryo in fresh or frozen cycle, while simultaneously reducing multiple pregnancies, at least among women with a good prognosis. The quality of evidence was low to moderate primarily due to inadequate reporting of study methods and absence of masking those delivering, as well as receiving the interventions.

Kamath MS ，Mascarenhas M ，Kirubakaran R ，Bhattacharya S ... -  《Cochrane Database of Systematic Reviews》

Number of embryos for transfer following in vitro fertilisation or intra-cytoplasmic sperm injection.

Pandian Z ，Marjoribanks J ，Ozturk O ，Serour G ，Bhattacharya S ... -  《Cochrane Database of Systematic Reviews》

Cumulative live birth rates after one ART cycle including all subsequent frozen-thaw cycles in 1050 women: secondary outcome of an RCT comparing GnRH-antagonist and GnRH-agonist protocols.

Are cumulative live birth rates (CLBRs) similar in GnRH-antagonist and GnRH-agonist protocols for the first ART cycle including all subsequent frozen-thaw cycles from the same oocyte retrieval? The chances of at least one live birth following utilization of all fresh and frozen embryos after the first ART cycle are similar in GnRH-antagonist and GnRH-agonist protocols. Reproductive outcomes of ART treatment are traditionally reported as pregnancies per cycle or per embryo transfer. However, the primary concern is the overall chance of a live birth. After the first ART cycle with fresh embryo transfer, we found live birth rates (LBRs) of 22.8% and 23.8% (P = 0.70) for the GnRH-antagonist and GnRH-agonist protocols, respectively. But with CLBRs including both fresh and frozen embryos from the first oocyte retrieval, chances of at least one live birth increases. There are no previous randomized controlled trials (RCTs) comparing CLBRs in GnRH-antagonist versus GnRH-agonist protocols. Previous studies on CLBR are either retrospective cohort studies including multiple fresh cycles or RCTs comparing single embryo transfer (SET) with double embryo transfer (DET). CLBR was a secondary outcome in a Phase IV, dual-center, open-label, RCT including 1050 women allocated to a short GnRH-antagonist or a long GnRH-agonist protocol in a 1:1 ratio over a 5-year period using a web-based concealed randomization code. The minimum follow-up time from the first IVF cycle was 2 years. The aim was to compare CLBR between the two groups following utilization of all fresh and frozen embryos from the first ART cycle. All women referred for their first ART cycle at two public fertility clinics, <40 years of age were approached. A total of 1050 subjects were allocated to treatment and 1023 women started standardized ART protocols with recombinant human follitropin-β (rFSH) stimulation. Day-2 SET was planned and additional embryos were frozen and used in subsequent frozen-thawed cycles. All pregnancies generated from oocyte retrieval during the first IVF cycle including fresh and frozen-thaw cycles were registered. Ongoing pregnancy was determined by ultrasonography at gestational week 7-9 and live birth was irrespective of the duration of gestation. CLBR was defined as at least one live birth per allocated woman after fresh and frozen cycles. Subjects were censored out after the first live birth. Cox proportional hazard model was used to evaluate the relative prognostic significance of female age, BMI, the number of retrieved oocytes and the diagnosis of infertility in relation to the CLBR. Baseline characteristics were similar and equal proportions of patients continued with frozen-thaw (frozen embryo transfer, FET) cycles after their fresh ART cycle in the GnRH-antagonist and GnRH-agonist arms. When combining all fresh and frozen-thaw embryo transfers from first oocyte retrieval with a minimum of 2-year follow-up, the CLBR was 34.1% (182/534) in the GnRH-antagonist group versus 31.2% (161/516) in the GnRH-agonist group (odds ratio (OR):1.14; 95% CI: 0.88-1.48, P = 0.32). Mean time to the first live birth was 11.0 months in the GnRH-antagonist group compared to 11.5 months in the GnRH-agonist group (P < 0.01). The total number of deliveries from all FET cycles where embryos were thawed were higher in the antagonist group 64/330 (19.4%) compared to the agonist group 43/355 (12.1%) ((OR): 1.74; 95% CI: 1.14-2.66, P = 0.01). The evaluation of prognostic factors showed that more retrieved oocytes were associated with a significantly higher CLBR in both treatment groups. For the subgroup of obese women (BMI >30 kg/m2), the CLBR was significantly higher in the GnRH-antagonist group (P = 0.02). The duration of the trial is a possible limitation with introduction of new methods as 'Freeze all' and 'GnRH-agonist triggering', but as these treatments were used in only few women, a systematic bias is not likely. Blastocyst culture of surplus embryos for freezing was introduced to both groups simultaneously, thereby minimizing the risk of bias. Furthermore, with a minimum of 2-year follow-up, a minority (<1%) still had cryopreserved embryos and no live birth at the end of the trial. The post hoc prognostic covariate analyses with multiple strata should be interpreted with caution. Finally, the physicians were not blinded to GnRH treatment group after randomization. With the improvement of embryo culture, freezing and thawing methods as well as a strategy of elective SET, CLBR until first live birth provides an all-inclusive success rate for ART. When comparing GnRH-antagonist and GnRH-agonist protocols, we find similar CLBRs, despite more oocytes being retrieved in the GnRH-agonist protocol. An unrestricted research grant is funded by Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA (MSD). The funders had no influence on the data collection, analyses or conclusions of the study. No conflict of interests to declare. EudraCT #: 2008-005452-24. ClinicalTrial.gov: NCT00756028. 18 September 2008. 14 January 2009.

Toftager M ，Bogstad J ，Løssl K ，Prætorius L ，Zedeler A ，Bryndorf T ，Nilas L ，Pinborg A ... -  《-》

Clinical outcomes after single-versus double-embryo transfers in women with adenomyosis: a retrospective study.

Guo J ，Zeng Z ，Li M ，Huang J ，Peng J ，Wang M ，Liang X ，Zeng H ... -  《-》