Comparison of Stimulated Cycles with Low Dose r-FSH versus Hormone Replacement Cycles for Endometrial Preparation Prior to Frozen-Thawed Embryo Transfer in Young Women with Polycystic Ovarian Syndrome: A Single-Center Retrospective Cohort Study from China

Endometrial preparation protocols did not impact pregnancy outcomes of patients with cured chronic endometritis

RESEARCH QUESTION

Do endometrial preparation protocols have an effect on pregnancy outcomes in patients with cured chronic endometritis?

DESIGN

A retrospective study was conducted on 3721 infertile patients from December 2018 to August 2020. Endometrial tissues obtained during the proliferative phase were immunostained for CD138. The presence of CD138-positive cells within the stromal cells indicated chronic endometritis. All patients diagnosed with chronic endometritis received oral antibiotics. Patients underwent endometrial preparation and frozen embryo transfer once chronic endometritis was cured. This study compared various endometrial preparation protocols to assess their effects on pregnancy outcomes. Additionally, it aimed to investigate differences in pregnancy outcomes between patients without chronic endometritis and patients with cured chronic endometritis while following the same endometrial preparation protocol.

RESULTS

Almost no differences in pregnancy outcomes were observed between natural cycle, hormone replacement therapy (HRT) and gonadotrophin-releasing hormone agonist-HRT (GnRH agonist-HRT) protocols in patients without chronic endometritis and patients with cured chronic endometritis. The only notable difference was that, among women without chronic endometritis, the early miscarriage rate was higher for the GnRH agonist-HRT protocol (25.8%) compared with the natural cycle (17.4%) and HRT (17.7%) protocols (P = 0.025). However, this difference was not significant after adjusting for confounders (adjusted OR 1.383, 95% CI 0.931-2.055). The live birth rate, clinical pregnancy rate, early miscarriage rate, ectopic pregnancy rate and ongoing pregnancy rate did not differ significantly (P > 0.05) between patients without chronic endometritis and patients with cured chronic endometritis who underwent natural cycle, HRT and GnRH agonist-HRT protocols.

CONCLUSION

Endometrial preparation protocols had no impact on pregnancy outcomes in patients with cured chronic endometritis.

Comparison of pregnancy outcomes of letrozole-induced frozen-thawed embryo transfer cycles in PCOS women with two different abnormal ovulation patterns: A retrospective cohort study

No studies have been conducted on the impact of different types of ovulatory dysfunction on the outcomes of frozen-thawed embryo transfers (FETs) in a letrozole-stimulated cycle in women with polycystic ovarian syndrome (PCOS). This study aimed to compare whether pregnancy outcomes of the letrozole-induced protocol in FET cycles differed between oligo-ovulatory and anovulatory women with PCOS. In a retrospective cohort study, women with PCOS who had undergone letrozole-induced FET at a university-affiliated fertility clinic from February 2014 to October 2020 were identified. The primary end point was live birth rate (LBR) per embryo transfer. Propensity score matching and multivariate logistic regression analyses were performed to control for the relevant confounders. A total of 652 women with PCOS undergoing letrozole-induced FET were included in the final analysis. Three hundred sixty-three of these women had oligo-ovulatory periods, while 289 had anovulatory periods. Propensity score matching analysis showed that LBR did not differ between groups (36.8% in oligo-ovulatory group vs 32.8% in anovulatory group, P = .431). Nevertheless, after controlling for potential confounding factors, LBR was significantly lower in anovulatory than oligo-ovulatory women (adjusted odds ratio 1.57, 95% confidence interval 1.08-2.29, P = .018). Furthermore, the pregnancy loss rate among the oligo-ovulatory group remained lower than those among the anovulatory group (adjusted odds ratio 0.23, 95% confidence interval 0.12-0.44, P < .001). Despite adjustment for confounding factors, those with oligo-ovulatory PCOS had a higher LBR and lower pregnancy loss rate compared with those with anovulatory PCOS. This may indicate that when oligo-ovulation is detected, PCOS patients should be intervened in time to conceive as soon as possible. Prospective studies must be conducted in the future to verify our findings.

Premature timing of progesterone luteal phase support initiation did not negatively impact live birth rates in modified natural frozen thawed embryo transfer cycles

Study question

In a modified natural cycle frozen-thawed embryo transfer (mNC-FET), does the premature timing of progesterone luteal phase support (LPS) initiation 24 h following human chorionic gonadotropin (hCG) trigger impact live birth?

Summary answer

Premature LPS initiation did not negatively affect the live birth rate (LBR) in mNC-FET cycles compared with conventional LPS initiation 48 h after hCG triggering.

What is known already

During natural cycle FET, human chorionic gonadotropin is routinely used to mimic endogenous luteinizing hormone (LH) surge to induce ovulation, which allows more flexibility in embryo transfer scheduling, thus relieving the burden of multiple visits by patients and laboratory workloads, which is also known as mNC-FET. Moreover, recent data demonstrates that ovulatory women undergoing natural cycle FETs have a lower risk of maternal and fetal complications due to the essential role of the corpus luteum in implantation, placentation and pregnancy maintenance. While several studies have confirmed the positive effects of LPS in mNC-FETs, the timing of progesterone LPS initiation is still unclear, as compared with fresh cycles where robust research has been conducted. To the best of our knowledge, no clinical studies comparing different beginning days in mNC-FET cycles have been published.

Study design size duration

This retrospective cohort study involved 756 mNC-FET cycles performed at a university-affiliated reproductive center between January 2019 and August 2021. The primary outcome measured was the LBR.

Participants/materials setting methods

Ovulatory women ≤42 years of age who were referred for their autologous mNC-FET cycles were included in the study. According to the timing of progesterone LPS initiation following the hCG trigger, patients were assigned into two categories: premature LPS group (progesterone initiation 24 h after hCG trigger, n = 182) versus conventional LPS group (progesterone initiation 48 h after hCG trigger, n = 574). Multivariate logistic regression analysis was used to control for confounding variables.

Main results and the role of chance

There were no differences in background characteristics between the two study groups, except for the proportion of assisted hatching (53.8% in premature LPS group versus 42.3% in conventional LPS group, p = 0.007). In the premature LPS group, 56 of 182 patients (30.8%) had a live birth, compared to 179 of 574 patients (31.2%) in the conventional LPS group, with no significant difference observed between groups (adjusted odds ratio [aOR] 0.98, 95% confidence interval [CI] 0.67-1.43, p = 0.913). In addition, there was no significant difference between the two groups in other secondary outcomes. A sensitivity analysis for LBR according to the serum LH and progesterone levels on hCG trigger day also confirmed the aforementioned findings.

Limitations reasons for caution

In this study, retrospective analysis was conducted in a single center and was therefore prone to bias. Additionally, we did not anticipate monitoring the patient's follicle rupture and ovulation after hCG triggering. Future prospective clinical trials remain necessary to confirm our results.

Wider implications of the findings

While exogenous progesterone LPS was added 24 h after hCG triggering, embryo-endometrium synchrony would not be adversely affected so long as sufficient time was allowed for endometrial exposure to exogenous progesterone. Our data support promising clinical outcomes following this event. As a result of our findings, clinicians and patients will be able to make better informed decisions.

Study funding/competing interests

No specific funding was available for this study. The authors have no personal conflicting interests to declare.

Trial registration number

N/A.

Systematic review update and meta-analysis of randomized and non-randomized controlled trials of ovarian stimulation versus artificial cycle for endometrial preparation prior to frozen embryo transfer in women with polycystic ovary syndrome

PURPOSE

This systematic review and meta-analysis aimed to compare the short-term reproductive and long-term obstetric outcomes after endometrial preparations by ovarian stimulation protocols and hormone replacement therapy (HRT) in women with polycystic ovary syndrome (PCOS) prior to frozen embryo transfer (FET).

METHOD

PubMed, EMBASE, Web of Science and the Cochrane Library were searched to identify relevant studies. Primary outcome was live birth rate, secondary outcomes included the rates of clinical pregnancy, miscarriage, implantation and hCG-postive, cycle cancellation, ectopic pregnancy, preterm birth, preeclampsia, gestational hypertension, gestational diabetes mellitus and abnormal placentation.

RESULTS

Nine studies, including 8327 patients with PCOS, were identified. Live birth rate was significantly higher (RR = 1.11, 95% CI = 1.03-1.19) and miscarriage rate (RR = 0.60, 95% CI = 0.46-0.78) was significantly lower in stimulated protocol compared to the rates in HRT. While the rates of ongoing pregnancy, clinical pregnancy, implantation, hCG-positive, cycle cancellation and ectopic pregnancy showed no significant difference between the two protocols. Compared HRT with different stimulation protocols, significantly higher clinical pregnancy rate (RR = 1.54, 95% CI = 1.20-1.98) were found in letrozole group, but not in the other subgroups. For the obstetric outcomes, the preterm birth and preeclampsia rates were significantly lower in the stimulated group compared to that in the HRT group (RR = 0.85, 95% CI = 0.74-0.98; RR = 0.57, 95% CI = 0.40-0.82, respectively), while gestational hypertension, gestational diabetes mellitus and abnormal placentation rates showed no significant difference.

CONCLUSIONS

The present data suggest that ovarian stimulation protocol as an endometrial preparation regimen prior to FET might be superior to HRT protocol with a significantly higher rate of live birth, lower risk of miscarriage, preterm birth and preeclampsia. Our study showed stimulated protocol is better than HRT regimen as an endometrial preparation for women with PCOS. However, quality of the evidence is low, more well-designed RCT studies are still needed to confirm the results before clinical recommendation, particularly direct comparisons between letrozole and other stimulated regimens.

Short (seven days) versus standard (fourteen days) oestrogen administration in a programmed frozen embryo transfer cycle: a retrospective cohort study

Research question

What influence does seven days of oestrogen administration versus fourteen days have on the reproductive outcomes of frozen-thawed embryo transfer (FET) in programmed endometrial preparation cycles?

Design

In a retrospective study, conducted at a university-affiliated tertiary hospital, a total of 2628 infertile patients (4142 FET cycles) were divided into one of two groups between January 2014 and December 2020: group A (n = 1406, seven days of oestrogen before progesterone (P4) supplementation) and group B (n = 2716, fourteen days of oestrogen before P4 supplementation). The primary outcome was cumulative live birth rate (CLBR). Secondary outcomes were other pregnancy-related outcomes, maternal and neonatal complications.

Results

No significant difference in CLBR was observed when comparing seven versus fourteen days of oestrogen administration before starting P4 supplementation (47.6% vs. 48.8%, P = 0.537). Furthermore, multivariable logistic regression analysis revealed that oestrogen administration in programmed FET cycles (7 days vs. 14 days) was not significantly associated with CLBR (OR 1.04, 95% CI 0.89–1.23). The risks of maternal and neonatal complications were comparable between the two groups.

Conclusions

Variation in the duration of oestradiol supplementation before P4 initiation does not impact FET reproductive outcomes. For infertile women who desire to conceive as soon as feasible, short (seven days) oestrogen administration in a programmed FET cycle may be a suitable alternative.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-022-00967-5.

Ovulation induction regimens are associated with a higher rate of livebirth after frozen single-blastocyst transfer among women with polycystic ovary syndrome

BACKGROUND

Hormone replacement therapy (HRT) regimen was suggested to be associated with a decreased rate of livebirth and a higher risk of hypertensive disorders of pregnancy (HDP) after frozen cleavage stage embryo transfer in women with polycystic ovary syndrome (PCOS). With the dramatically increased use of elective single embryo transfer, there is great need to explore the impacts of different endometrial preparation regimens on frozen single-blastocyst transfer in women with PCOS.

METHODS

In this study, a total of 3941 women who diagnosed with PCOS and underwent single-blastocyst transfer during their first cycles of frozen embryo transfer (FET) between March 2012 and December 2020 were included. We retrospectively compared the pregnancy and neonatal outcomes after frozen single-blastocyst transfer with endometrial preparation by HRT regimen (n = 3540), ovulation induction by human menopausal gonadotropin (hMG) regimen (n = 226), and ovulation induction by letrozole regimen (n = 175).

RESULTS

After adjustment for confounders with multivariable logistic regression, the hMG regimen group [(58.4% vs. 49.6%; adjusted odds ratio (aOR): 1.43; 95% confidence interval (CI): 1.09-1.89)] and letrozole regimen group (58.9% vs. 49.6%; aOR: 1.42; 95% CI: 1.04-1.93) were associated with a higher rate of livebirth (primary outcome), compared with the group with HRT regimen. As to the secondary outcomes, the rate of pregnancy loss in the hMG regimen group (22.8% vs. 30.3%; aOR: 0.69; 95% CI: 0.48-1.00) and letrozole regimen group (16.9% vs. 30.3%; aOR: 0.48; 95% CI: 0.30-0.78) was also lower than that in the HRT regimen group. The pregnancy outcomes between the hMG regimen group and the letrozole regimen group were similar. We did not observe significant difference in the incidences of maternal and neonatal complications among these three groups.

CONCLUSION

Ovulation induction regimen with letrozole or hMG for endometrial preparation was associated with a higher livebirth rate and a lower pregnancy loss rate in frozen single-blastocyst transfer cycles among women with PCOS.

Is Human Chorionic Gonadotropin Trigger Beneficial for Natural Cycle Frozen-Thawed Embryo Transfer?

Objective: The aim of this study is to investigate, in ovulatory patients, whether there is a difference in reproductive outcomes following frozen-thawed embryo transfer (FET) in natural cycles (NC) compared to modified natural cycles (mNC).

Methods: This retrospective cohort study, performed at the public tertiary fertility clinic, involved all infertile patients undergoing endometrial preparation prior to FET in NC and mNC from January, 2017 to November, 2020. One thousand hundred and sixty-two patients were divided into two groups: mNC group (n = 248) had FET in a NC after ovulation triggering with human chorionic gonadotropin (hCG); NC group (n = 914) had FET in a NC after spontaneous ovulation were observed. The primary outcome was live birth rate. All pregnancy outcomes were analyzed by propensity score matching (PSM) and multivariable logistic regression analyses.

Results: The NC group showed a higher live birth rate [344/914 (37.6%) vs. 68/248 (27.4%), P = 0.003; 87/240 (36.3%) vs. 66/240 (27.5%), P = 0.040] than the mNC group before and after PSM analysis. Multivariable analysis also showed mNC to be associated with a decreased likelihood of live birth compared with NC [odds ratio (OR) 95% confidence interval (CI) 0.71 (0.51–0.98), P = 0.039].

Conclusion: For women with regular menstrual cycles, NC-FET may have a higher chance of live birth than that in the mNC-FET cycles. As a consequence, it's critical to avoid hCG triggering as much as possible when FETs utilize a natural cycle strategy for endometrial preparation. Nevertheless, further more well-designed randomized clinical trials are still needed to determine this finding.