Comparison of pregnancy rates following fresh and frozen embryo transfer in women undergoing assisted reproductive techniques

Freezing embryos is the best way to increase fertility for women with ovarian hyper-stimulation syndrome and women at risk for ovarian dysfunction. Due to the importance of freezing and pregnancy embryos, the present study was conducted to compare the fertility rate and the affecting factors following fresh embryos and frozen embryos in women treated with assisted reproductive techniques. In this study, 250 infertile women and IVF/ICSI candidates were studied. Embryos were used in fresh or frozen groups for transfer to the uterus. The expression of the caspase-3 gene was also examined for further evaluation. Data analysis was performed using SPSS 16 software, Chi-square, independent t-test, and Kruskal-Wallis tests. Out of 250 infertile women, 96 (38.4%) became pregnant, of which 54 were in the fresh embryo group and 42 were in the frozen embryo group, which was not statistically significant (P=0.32). Infertility causes, number of embryonic cells and grading of transferred embryos, delivery complications, embryo implantation methods, number of produced embryos after delivery, and endometrial thickness were not significantly different between the two groups (P=0.53). The difference between the mean number of transferred embryos in the two groups was significant (P<0.05), which was no longer significant after excluding non-pregnant women, and in comparing with only pregnant women (P=0.36). The result of caspase-3 gene expression showed that there was significant differences between fresh embryos, healthy thawed frozen embryos, and destroyed thawed frozen embryos. But these results were totally different from the results of the Pregnancy rate section. Therefore, it is inferred that although caspase-3 genes are expressed in frozen embryos after thawing and are ready to destroy the embryo, there are probably a number of involved factors that prevent the activity of caspase-3 and do not allow the apoptotic process to occur. What these factors are and how they prevent this process needs further study.

Two modified natural in vitro fertilisation (IVF) protocols compared to conventional IVF treatment: Retrospective data from one Danish Fertility Centre

Aim of study: Over the last decade, laboratory procedures in in vitro fertilisation (IVF) have improved. Hyperstimulated ovaries cause an overload of surplus embryos. The present study was designed to evaluate the efficiency of two different modified IVF cycle protocols trying to reduce the load of medication used for IVF: simple IVF (S-IVF), Tamoxifen 40 mg daily from day 2 in the cycle to ovulation induction) and mild IVF (M-IVF), Tamoxifen 40 mg daily and every secondary 150 IU Gonal F until ovulation induction. The study aims to evaluate their efficiency compared with our conventional IVF (C-IVF) using a short antagonist protocol. Methods: A retrospective cohort study including all patients admitted to IVF for unexplained infertility, tubal factor, and male factor. In all stimulated cycles patients aimed at having fresh embryos transferred and surplus good embryos cryopreserved. All patients were recruited in the same period and allocated to the different treatments on their own request. The study was conducted between June 2019 and February 2021. Results: In total the study included 976 IVF cycles. 651 cycles from C-IVF, 145 cycles from S-IVF and 180 cycles from M-IVF. Mean age in the groups were comparable. Mean number of eggs retrieved was 6.1 (C-IVF), 1.2 (S-IVF) and 3.0 (M-IVF). Pregnancy rate per fresh transfer was found to be 29% for C-IVF, 26% in the S-IVF group and for the M-IVF 20%. Conclusion: Modified IVF stimulation protocols may be an important step towards a simpler assisted reproductive technology (ART) approach. More tolerable for women, easier and cheaper for patients and society they maintain acceptable clinical pregnancy rates. Large prospective studies need to be performed in the future.

P–701 Fresh vs frozen PGT-A cycles in donor oocyte recipients

Study question For donor oocyte recipients, are clinical outcomes superior for fresh versus frozen euploid embryos? Summary answer Among donor oocyte recipients receiving euploid embryos, fresh embryos are associated with superior clinical outcomes when compared with frozen embryos. What is known already A recent large retrospective cohort national registry study reported that among donor oocyte recipients, fresh embryos were associated with better clinical outcomes when compared with frozen embryos. This finding contrast with data from autologous oocytes. Since embryo quality at embryo transfer (ET) may introduce a significant confounder, the additional analysis of recipients receiving only euploid embryos may add important information on the subject. Study design, size, duration Retrospective cohort analysis of PGT-A IVF-cycles of women using donor oocytes resulting in fresh blastocyst ET compared to the first frozen blastocyst ET from freeze-all cycles between 2014 and 2020 at Instituto Bernabeu, Alicante, Spain. A total of 349 donor oocyte cycles were analyzed, in which 211 were fresh and 138 were frozen ETs. Thawed oocytes were not excluded. Participants/materials, setting, methods Clinical pregnancy (gestational sac plus embryo heart beating at 6–7 weeks), was the primary outcome measure. Secondary outcomes included pregnancy and early pregnancy loss rate. aCGH platform tested the embryos transferred in fresh whereas either aCGH or NGS platforms were used for embryos submitted to elective frozen cycles. Vitrification was used as cryopreservation technique. Fresh transfers were performed in artificial cycles. Different types of endometrial preparations were used for FET in the study. Main results and the role of chance Recipients in the fresh group were significantly younger and had more embryos transferred compared to the frozen group (41.3 vs 42.5 and 1.2 vs 1.1, respectively). More clinical pregnancies were observed in the fresh compared to the frozen group (108/211 versus 54/138, respectively, odds ratio (ODR) 1.63 [95% CI 1.05–2.52]; p = 0.02). Pregnancy rates were also higher in the fresh compared to the frozen group (128/211 versus 63/138, respectively, odds ratio (ODR) 1.83 [95% CI 1.18–2.83]; p = 0.005). Early pregnancy losses were similar in both groups (p = 0.2). Limitations, reasons for caution Implantation failure and abnormal male tests were the most frequent indications for PGT-A. Because of the observational nature of the results in this limited sample size, a cause–effect relationship should not be assumed; evidence from larger well-designed randomized control trials is still required before clinical advice can be suggested. Wider implications of the findings: When PGT-A analysis is deemed to be necessary in oocyte recipients, cryopreservation may have an adverse impact on IVF outcomes. Future studies exploring ET in natural vs artificial cycles are warranted to further isolate the impact of vitrification and the uterine environment on IVF outcomes. Trial registration number Not applicable

Predictive value of the number of frozen blastocysts in live birth rates of the transferred fresh embryos

Background Blastocyst development by extended culture in vitro allows the embryos to ‘select’ themselves, thus successful growth to the blastocyst stage is a reflection of the developmental competence of cleavage stage embryos in a cohort. The study aims to determine whether the number of frozen blastocysts is associated with live birth rates of the transferred fresh embryos. Method The retrospective study included 8676 cycles of first fresh embryo transfer from January 2016 to June 2019 at a fertility center of a university hospital. The patients with ≥ 10 oocytes retrieved were divided into three groups according to the number of frozen blastocysts: 0 (group 1), 1–2 (group 2), and ≥ 3 (group 3). The primary outcome measure was the live birth. The secondary outcome measures included clinical pregnancy rates and implantation rates. Logistic regression analysis was also performed. Results Live birth rates in patients with ≥ 3 and 1–2 frozen blastocysts were 47.6% and 46.1%, respectively, which were significantly higher than that in patients without blastocyst (36.0%). The clinical pregnancy rate in group 3 was 65.1%, which was also significantly higher than the other two groups (47.0% and 59.2%). The implantation rates were 35.5%, 47.6%, and 56.0% in the three groups, respectively (P < 0.001). Compared with groups of frozen blastocysts, 0 frozen blastocyst yielded a lower rate of live birth (the adjusted odds ratio: 0.526, 95% CI: 0.469, 0.612). Conclusion In patients with optimal ovarian response that retrieved ≥ 10 oocytes, fresh embryos transfer followed by having blastocysts frozen is a strong indicator of pregnancy achievement, but the number of frozen blastocysts (if not = 0) has limited value in predicting live birth rates.

Supraphysiological estradiol levels on the hCG trigger day are associated with SGA for singletons born from fresh embryo transfer

The effects of supraphysiological estradiol (E2) on neonatal outcomes and the significance of specific E2 concentrations remain unclear. The purpose of this study was to investigate whether supraphysiological E2 levels on the human chorionic gonadotropin (hCG) trigger day are associated with small size for gestational age (SGA) in singletons born from fresh embryo transfer (ET) cycles. Patients with singleton pregnancies who delivered after the transfer of fresh embryos, during the period from July 2012 to December 2017, at our center were included. We excluded cycles involving a vanishing twin, maternal age >35 years, basal follicle-stimulating hormone ≥10 mIU/ml, or anti-Müllerian hormone ≤1 ng/ml. We then divided all cycles into five groups by E2 level on trigger day: group A, <2000 pg/ml (reference group); group B, 2000 pg/ml≤E2<2999 pg/ml; group C, 3000 pg/ml≤E2<3999 pg/ml; group D, 4000 pg/ml≤E2<4999 pg/ml; and group E, ≥5000 pg/ml. The prevalence of SGA among singletons from fresh ET was the primary outcome. The SGA rate significantly increased when the E2 level was ≥4000 pg/ml, as observed by comparing groups D (odds ratio [OR]: 1·79, 95% confidence interval [CI]: 1·16–2·76, P = 0·01) and E (OR: 1·68, 95% CI: 1·10–2·56, P = 0·02) with the reference group. Multivariate logistic regression indicated that a serum E2 level of at least 4000 pg/ml on the hCG trigger day was associated with increased SGA and with significant differences for groups D (adjusted OR [AOR]: 1·65, 95% CI: 1·05–2·59, P = 0·03) and E (AOR: 1·60, 95% CI: 1·03–2·53, P = 0·04) relative to the reference group. In conclusion, in fresh ET cycles, the supraphysiological E2 ≥4000 pg/ml on the hCG trigger day increases the risk of SGA.

THE EFFECTIVENESS OF PROGRAMS AND THE COURSE OF PREGNANCY DURING THE TRANSFER OF THAWED AND FRESH EMBRYOS

In recent years, IVF programs have been increasingly carried out in which cryopreserved embryos are used. Along with these programs, IVF procedures are carried out, in which "fresh" embryos are transferred. The problem of choice naturally arises before reproductive specialists: which program to give preference to - FRESH and FET? Specialists of the Institute of Reproductive Medicine (Almaty, RK) conducted a number of observations. After careful sampling of these data, no differences in CNB% were found in Fresh and FET (Frozen Embryo Transfer) programs. The incidence of complications during pregnancy and childbirth with FET protocols was significantly higher in comparison with Fresh, which requires further study. When analyzing the "Take home baby" indicator, there were no statistically significant differences between the FET and Fresh protocols.

Supraphysiological estradiol levels on the hCG trigger day are associated with SGA for singletons born from fresh embryo transfer

The effects of supraphysiological estradiol (E2) on neonatal outcomes and the significance of specific E2 concentrations remain unclear. The purpose of this study was investigate whether supraphysiological E2 levels on the hCG trigger day are associated with small size for gestational age (SGA) in singletons born from fresh embryo transfer (ET) cycles. Patients with singleton pregnancies with delivered after transfer of fresh embryos, during the period of July 2012 to December 2017 at our center were included. We excluded cycles involving a vanishing twin, maternal age >35 years, basal FSH ≥10 mIU/ml, AMH ≤1 ng/ml or incomplete records. We then divided all cycles into 5 groups by E2 level on the day of hCG trigger: group A, <2000 pg/ml (reference group); group B, 2000 pg/ml≤E2<2999 pg/ml; group C, 3000 pg/ml≤E2<3999 pg/ml; group D, 4000 pg/ml≤E2<4999 pg/ml; and group E, ≥5000 pg/ml. The prevalence of SGA among singletons from fresh ET was the primary outcome. The SGA rate significantly increased when the E2 level was ≥4000 pg/ml, as observed by comparing groups D (odds ratio [OR]: 1.79, 95% confidence interval [CI]: 1.16–2.76, P=0.01) and E (OR: 1.68, 95% CI: 1.10–2.56, P=0.02) with the reference group. Multivariate logistic regression indicated that a serum E2 level of at least 4000 pg/ml on the hCG trigger day was associated with increased SGA and with significant differences for groups D (adjusted OR [AOR]: 1.65, 95% CI: 1.05–2.59, P=0.03) and E (AOR: 1.60, 95% CI: 1.03–2.53, P=0.04) relative to the reference group. In conclusion，for fresh ET cycles, supraphysiological E2 ≥4000 pg/ml on the hCG trigger day increases the risk of singleton SGA.