Freezing of all embryos in in vitro fertilization is beneficial in high responders, but not intermediate and low responders: an analysis of 82,935 cycles from the Society for Assisted Reproductive Technology registry

Both high and low HCG day progesterone concentrations negatively affect live birth rates in IVF/ICSI cycles

RESEARCH QUESTION

Can previous reports of a decreased probability of success in stimulated IVF cycles with premature rise of progesterone, as determined by progesterone concentration on HCG day (PHCG), be confirmed?

DESIGN

Retrospective, observational, single-centre cohort study conducted on 5447 IVF and intracytoplasmic (ICSI) cycles carried out among 2192 patients between 2009 and 2015, with conventional ovarian stimulation. This large database was used to develop a non-linear mixed prognosis model of live birth rate (LBR) incorporating PHCG as a predictor.

RESULTS

In addition to known predictors (age, body mass index, anti-Müllerian hormone, type of infertility), PHCG was associated with a linear effect (OR 0.78 per Log[PHCG]ng/ml, 95% CI 0.611 to 0.997, P = 0.047) combined with a strong quadratic effect (OR 0.585 per Log²(PHCG)ng/ml, 95% CI 0.444 to 0.775, P < 0.001) resulting into a parabolic reverse-U curve. A significant interaction (P = 0.038) was found between PHCG and number of oocytes if three or less, but the effect of PHCG remains modest. For higher oocyte numbers, LBR rapidly increases with number of retrieved oocytes; however, LBR becomes more sensitive to PHCG as the number of oocytes increases. Higher live birth prognoses occur for optimal PHCG but are sharply reduced for lower or higher PHCG.

CONCLUSIONS

Evidence is provided of an important negative effect of PHCG at lower and higher values, independent of oocyte number, thus defining appropriate ranges for fresh embryo transfer or freeze-all strategy. In poor responders, premature progesterone rise may be ignored, thus avoiding unnecessary cancellations or embryo freezing. Conversely, in higher responders, the negative effect of progesterone elevation is more pronounced, suggesting that freeze-all policy should be applied more widely.

Effect of body mass index on pregnancy outcomes in a freeze-all policy: an analysis of 22,043 first autologous frozen-thawed embryo transfer cycles in China

BACKGROUND

Abnormal BMI is associated with discouraging IVF outcomes in fresh autologous or oocyte donor cycles, whether or not such a relation also holds true for women undergoing frozen-thawed embryo transfer (FET) remains unknown. In addition, it remains unclear the detrimental effect of abnormal BMI on IVF outcomes occurs at the level of ovary or endometrium.

METHODS

A retrospective study involved 22,043 first FET cycles of all women who had undergone a freeze-all policy during the period from January 2010 to June 2017. To control for the embryo factor, our analysis was restricted to women with high-quality embryo transfer. The main outcome measure was live birth rate per embryo transfer. The secondary endpoints included rates of implantation, clinical pregnancy, multiple pregnancy, and pregnancy loss. Multivariate logistic regression analysis was performed to detect the independent effect of BMI on live birth rate after adjusting for important confounding variables.

RESULTS

In the crude analysis, reproductive outcomes were similar between underweight women and normal-weight controls whereas all parameter outcomes were significantly worse in patients with obesity. After adjustment for a number of confounding factors, underweight women had a marginally significant decrease in rates of implantation (adjusted odds ratio (aOR) 0.91; 95% CI 0.85-0.96), clinical pregnancy (aOR 0.91; 95% CI 0.83-0.99), and live birth (aOR 0.91; 95% CI 0.83-0.99) as compared to the women with normal weight. Obesity was significantly associated with decreased implantation (aOR 0.80; 95% CI 0.73-0.87), clinical pregnancy (aOR 0.81; 95% CI 0.71-0.91), and live birth rates (aOR 0.70; 95% CI 0.62-0.80). Moreover, the pregnancy loss rate, both in the first (aOR 1.46; 95% CI 1.15-1.87) and in the second trimester (aOR 2.76; 95% CI 1.67-4.58), was significantly higher in the obesity group than that in the reference group.

CONCLUSIONS

Among women undergoing first FET with high-quality embryo transfer, low BMI has limited impact on pregnancy and live birth rates. On the contrary, obesity was associated with worse IVF outcomes. Our findings further highlighted that endometrial receptivity played an important role in the poor reproductive outcomes of women with abnormal weight status.

Evaluation of progestogen supplementation for luteal phase support in fresh in vitro fertilization cycles

OBJECTIVE

To evaluate the effectiveness of progestogen supplementation in improving clinical pregnancy rates in women undergoing fresh IVF cycles and to compare different routes, start times, durations, and estrogen coadministration regimen.

DESIGN

Comprehensive systematic review and meta-analysis.

SETTING

University.

PATIENT(S)

Women undergoing fresh IVF cycles who did and did not receive progestogen supplementation.

INTERVENTION(S)

Summary odds ratios (ORs) were calculated by binomial logistic regression.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy rates.

RESULT(S)

Eighty-two articles (26,726 women) were included. Clinical pregnancy rates were increased by IM (OR = 4.57), vaginal (OR = 3.34), SC (OR = 3.36), or oral (OR = 2.57) progestogen supplementation versus no treatment. The greatest benefit was observed when progestogens were supplemented IM versus vaginally (OR = 1.37). The optimal time to commence administration was between oocyte retrieval and ET (OR = 1.31), with oocyte retrieval +1 day being most beneficial. Coadministration of estrogen had no benefit (OR = 1.33), whether progestogens were coadministered vaginally or IM. Clinical pregnancy rates were equivalent when progestogen supplementation was ceased after ≤3 weeks or continued for up to 12 weeks (OR = 1.06).

CONCLUSION(S)

This broad-ranging meta-analysis highlights the need to reevaluate current clinical practice. The use of progestogens in fresh IVF cycles is substantially beneficial to clinical pregnancy. Critically, the use of IM progestogens should not be dismissed, as it yielded the greatest clinical pregnancy rates. Pregnancy success was impacted by initiation of therapy, with 1 day after oocyte retrieval being optimal. There is little evidence to support coadministration of estrogen or prolonging progestogen treatment beyond 3 weeks.

Cumulative live birth rates following a 'freeze-all' strategy: a population-based study

STUDY QUESTION

What is the cumulative live birth rate following a 'freeze-all' strategy compared with a 'fresh-transfer' strategy?

SUMMARY ANSWER

The 'freeze-all' strategy resulted in a similar cumulative live birth rate as the 'fresh-transfer' strategy among high responders (>15 oocytes retrieved) but did not benefit normal (10-15 oocytes) and suboptimal responders (<10 oocytes).

WHAT IS KNOWN ALREADY

Frozen-thawed embryo transfer is associated with a decreased risk of adverse obstetric and perinatal outcomes compared with fresh embryo transfer. It is unclear whether the 'freeze-all' strategy should be offered to all women undergoing ART treatment.

STUDY DESIGN SIZE DURATION

A population-based retrospective cohort study using data collected by the Victorian Assisted Reproductive Treatment Authority. This study included 14 331 women undergoing their first stimulated ART cycle with at least one oocyte fertilised between 1 July 2009 and 30 June 2014 in Victoria, Australia. Demographic characteristics, type of ART procedures and resulting pregnancy and birth outcomes were recorded for the stimulated cycle and associated thaw cycles until 30 June 2016, or until a live birth was achieved, or until all embryos from the stimulated cycle had been used.

PARTICIPANTS/MATERIALS SETTING METHODS

Women were grouped by whether they had undergone the 'freeze-all' strategy (n = 1028) where all embryos were cryopreserved for future transfer, or the 'fresh-transfer' strategy (n = 13 303) where selected embryo(s) were transferred in the stimulated cycle, and remaining embryo(s) were cryopreserved for future use. A discrete-time survival model was used to evaluate the cumulative live birth rate following 'freeze-all' and 'fresh-transfer' strategy.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 1028 women undergoing 'freeze-all' strategy and 13 303 women undergoing 'fresh-transfer' strategy had 1788 and 22 334 embryo transfer cycles resulting in 452 and 5126 live births, respectively. Most women (61.3%) in the 'freeze-all' group had more than 15 oocytes retrieved in the stimulated cycle compared with 18.1% of women in the 'fresh-transfer' group (P < 0.001). For high responders (>15 oocytes), the cumulative live birth rate in the 'freeze-all' group was similar to the 'fresh-transfer' group (56.8% vs. 56.2%, adjusted hazard ratio (AHR) 0.90, 95% CI 0.77-1.04). However, the likelihood of a live birth was lower in the 'freeze-all' group compared with the 'fresh-transfer' group among normal responders (10-15 oocytes) (33.2% vs. 46.3%, AHR 0.62, 95% CI 0.46-0.83) and suboptimal responders (<10 oocytes) (14.6% vs. 28.0%, AHR 0.67, 95% CI 0.14-1.01). During the minimum follow-up time of 2 years, 34.1%, 24.4% and 8.4% of suboptimal, normal and high responders, respectively, in the 'freeze-all' group did not return for any embryo transfer after the stimulated cycle, whereas all women in the 'fresh-transfer' group had at least one embryo transferred in the stimulated cycle.

LIMITATIONS REASONS FOR CAUTION

A limitation of this population-based study is the lack of information available on clinic-specific protocols for the 'freeze-all' strategy and the potential impact of these on outcomes. Data were not available on whether the 'freeze-all' strategy was used to prevent ovarian hyperstimulation syndrome (OHSS).

WIDER IMPLICATIONS OF THE FINDINGS

This study presents population-based evidence on clinical efficacy associated with a 'freeze-all' and 'fresh-transfer' strategy. The 'freeze-all' strategy may benefit some subgroups of patients, including women who are high responders and those who are at risk of OHSS, but should not be offered universally. Clinicians should consider the potential impact of electively deferring embryo transfer on treatment discontinuation in choosing the optimal embryo transfer strategy for couples undergoing ART treatment.

STUDY FUNDING/COMPETING INTERESTS

No specific funding was received to undertake this study. There is no conflict of interest, except that M.B. is a shareholder in Genea Ltd.

In Freeze-All Strategy, Cumulative Live Birth Rate (CLBR) Is Increasing According to the Number of Blastocysts Formed in Women <40 Undergoing Intracytoplasmic Sperm Injection (ICSI)

Background: Elective freezing of all embryos, followed by frozen-thawed ET cycles emerged to prevent risk of Ovarian Hyperstimulation Syndrome and to allow endometrium recovery after Controlled Ovarian Stimulation, leading to better IVF outcomes. Blastocyst Freeze-all policy can minimize the number of abnormal embryos and consequently failed ETs, but its efficacy in terms of cumulative rates has not been studied yet. Methods: A prospective cohort observational study was carried out in Assisting Nature, Center of Assisted Reproduction and Genetics, in Thessaloniki, Greece from January 2014 until December 2017. 244 patients- normal or high responders- underwent COS with recFSH and Freeze-all policy with blastocyst culture. The included patients were 18-39 years and achieved clinical pregnancy and/or live birth or had all their vitrified blastocysts transferred in subsequent frozen-thawed cycles. Women were divided into four groups (group A: 1-2 blastocysts frozen; group B: 3-4; group C: 5-6; group D ≥7 blastocysts frozen) or seven groups (group I: 1-2 blastocysts frozen, group II: 3, group III: 4, group IV: 5, group V: 6, group VI: 7; group VII: ≥8 blastocysts frozen), according to the numerical range or to the absolute number of vitrified blastocysts, respectively. Results: The main outcome of the study was the CLBR achieved by frozen-thawed ETs, according to the number of the vitrified blastocysts. Higher CLBR are expected, when at least 3 blastocysts are formed (group B: 65.2%) and at least 2 frozen-thawed ETs are performed, reaching highest rates (88%) by group D (≥7 vitrified blastocysts). Similarly, CLBR is significantly increasing with the absolute number of the vitrified blastocysts, ranging from 20%, when 1-2 blastocysts are vitrified (group I) to 82.4% when ≥8 blastocysts are available. Conclusions: A higher number of vitrified blastocysts is associated with higher CLBR in women <40 years old- normal/high responders- following Freeze-all policy. Adopting Freeze-all strategy after blastocyst culture can contribute to improve delivery outcome after IVF, in terms of CLBR. The number of the total cryopreserved blastocysts produced might reflect the quality of the oocyte and can successfully predict the pregnancy outcome. The blastulation rate can be a robust criterion to segment or not an IVF cycle.

Fertility and Neonatal Outcomes of Freeze-All vs. Fresh Embryo Transfer in Women With Advanced Endometriosis

Background: Eutopic endometrium from women with endometriosis has functional changes in several aspects, which may largely account for the decrease in the quality of endometrial receptivity. It is of utmost importance to know whether freeze-all strategy can restore optimal receptivity in endometriotic women leading to the better ART outcomes. Methods: Retrospective study involved patients with advanced endometriosis undergoing first embryo transfer cycles during the period from March 2006 to March 2017 at a tertiary care center. After propensity score matching, there were 506 women in the freeze-all group and 255 women in fresh group. Our main outcomes included the rates of implantation, clinical pregnancy, and live birth. Subgroup analyses were performed after stratification by the number of oocytes retrieved and fertilization method. Neonatal outcomes included gestational age and birth weight z-score for singletons and multiple births. Results: In our matched cohort, the implantation, clinical pregnancy and live birth rates were statistically significantly higher in the freeze-all group compared with fresh transfer groups (34.4 vs. 25.5%, 51.8 vs. 38.8%, and 45.3 vs. 31.8%, all P < 0.001, respectively). A more beneficial effect of freeze-all cycles was found in patients who got more than 15 oocytes. Additionally, when ICSI insemination techniques were used to achieve fertilization, the advantage of freeze-all strategy was not obvious. Assessment of 382 babies showed no statistically significant difference in the mode of delivery, sex of live-born, gestational age, unadjusted median birth weight, and z-score between two study groups. Conclusion: Freeze-all strategy is an attractive option to improve the outcomes of ART for women with advanced endometriosis.