Transdermal versus oral estrogen: clinical outcomes in patients undergoing frozen-thawed single blastocyst transfer cycles without GnRHa suppression, a prospective randomized clinical trial

Effect of estrogen exposure on pregnancy outcomes in artificial frozen-thawed embryo transfer cycles

In contemporary times, the employment of vitrification freezing technology has led to the widespread adoption of frozen-thawed embryo transfer (FET) worldwide. Meanwhile, hormone replacement therapy (HRT) is a crucial protocol for priming the endometrium during FET cycles. Estrogen is required in HRT cycles for the induction of progesterone receptors and to promote endometrial thickness. However, there is no universal consensus on the treatment duration, dosage regimen, administration route, and target serum estrogen levels. Therefore, this study aimed to offer a comprehensive review of these topics. A shorter duration of estrogen exposure may elevate the risk of early miscarriage, while prolonged exposure to estrogen does not seem to confer advantages to general population and may be attempted in individuals with thin endometrium. Moreover, excessive estrogen levels on the day of progesterone administration may be associated with higher miscarriage rates and lower live birth rates (LBR). To offer more comprehensive guidance for clinical practice, extensive and prospective studies involving a large sample size are warranted to determine the optimal concentration and duration of estrogen exposure.

A randomized clinical trial of transdermal (gel) versus oral estrogen for endometrial preparation in frozen embryo transfer cycle

OBJECTIVE

The aim of this study was to compare endometrial thickness with the use of transdermal estrogen (gel) versus oral estrogen (pills) for endometrial preparation in the frozen embryo transfer cycle and serum estrogen concentrations during the preparation cycle, side effects, and chemical and clinical pregnancy rates.

METHODS

This was a prospective, randomized controlled trial of women undergoing endometrial preparation for cryopreserved blastocyst transfer. A total of 88 women were randomized, of which 82 completed the study protocol. Of this group, 44 received 6 mg/day of estradiol valerate orally (pills group) and 38 received 4.5 mg/day of estradiol hemihydrate transdermally (gel group). Endometrial thickness was measured using transvaginal ultrasound between the 7 and 10th day of the cycle. Serum estradiol concentrations were measured on the day of initiating the cycle, on control transvaginal ultrasounds, and on the day of embryo transfer. Side effects were documented at each study visit. p<0.05 were adopted as statistically significant. The groups were compared using Student's t-test for continuous variables and chi-square or Fisher's exact test for categorical variables.

RESULTS

There were no significant group differences (p>0.05) in endometrial thickness, biochemical and clinical pregnancy rates, miscarriage rate, blood estradiol concentrations, duration of estradiol administration, or cycle cancellation rates.

CONCLUSION

Endometrial preparation with transdermal estrogen yielded similar reproductive outcomes to oral estrogen with fewer side effects.

Preparation of the endometrium for frozen embryo transfer: an update on clinical practices

Over the past decade, the application of frozen-thawed embryo transfer treatment cycles has increased substantially. Hormone replacement therapy and the natural cycle are two popular methods for preparing the endometrium. Hormone replacement therapy is now used at the discretion of the doctors because it is easy to coordinate the timing of embryo thawing and transfer with the schedules of the in-vitro fertilization lab, the treating doctors, and the patient. However, current results suggest that establishing a pregnancy in the absence of a corpus luteum as a result of anovulation may pose significant maternal and fetal risks. Therefore, a 'back to nature' approach that advocates an expanded use of natural cycle FET in ovulatory women has been suggested. Currently, there is increasing interest in how the method of endometrial preparation may influence frozen embryo transfer outcomes specifically, especially when it comes to details such as different types of ovulation monitoring and different luteal support in natural cycles, and the ideal exogenous hormone administration route as well as the endocrine monitoring in hormone replacement cycles. In addition to improving implantation rates and ensuring the safety of the fetus, addressing these points will allow for individualized endometrial preparation, also as few cycles as possible would be canceled.

Neutrophil-to-lymphocyte ratio is a predictor of biochemical miscarriage following artificial frozen embryo transfer cycles

The aim of this study is to examine the relationship between complete blood count (CBC) inflammatory markers and pregnancy outcome following artificial frozen embryo transfer cycles (AC-FET). This was a retrospective cohort study including 183 patients undergoing an AC-FET. The inflammatory markers including white blood cell count (WCC), neutrophil and lymphocyte count, neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) were compared between cycles with and without clinical pregnancies. Furthermore, these markers were compared between pregnancies with and without biochemical and clinical miscarriages. NLR was significantly higher in cycles with biochemical miscarriages (p = 0.009). Receiver operating curve analysis was performed to assess the role of NLR in predicting biochemical pregnancy. The area under the curve was 0.714 (95% confidence interval; 0.578-0.850, p = 0.009). The optimal cut-off value for NLR that was associated with biochemical miscarriage was 2.48 with 63% sensitivity and 75% specificity. A logistic regression analysis was performed with biochemical miscarriage as the dependent variable. An NLR value below 2.48 was an independent variable to affect biochemical miscarriage (OR: 0.2, 95% CI 0.05-0.92, p = 0.030). NLR emerged as a reliable predictor of biochemical miscarriage in AC-FET.Impact StatementWhat is already known on this subject? NLR and PLR are novel markers of inflammation. They are related to various gynecological and obstetric conditions including spontaneous abortion, preeclampsia. These markers are also associated with assisted reproductive technology success in fresh cycles.What the results of this study add? This is the first study to investigate the association of these markers with FET cycles. Our results have shown that cycles that ended in biochemical miscarriage had a significantly higher NLR compared with cycles continuing as a clinical pregnancy. An NLR value above 2.48 was predictive of biochemical miscarriage following AC-FET.What the implications are of these findings for clinical practice and/or further research? A high NLR level might have a significant value for the identification of patients at risk of biochemical miscarriage. Future research should assess the impact of anti-inflammatory agents on pregnancy outcomes in patient populations where systemic inflammation is documented by CBC inflammatory markers.

Is duration of estrogen supplementation associated with clinical outcomes in frozen-thawed autologous single-blastocyst transfer cycles?

PURPOSE

To investigate the relationship between different duration of estrogen administration and live birth rate (LBR) after autologous single frozen blastocyst transfer with hormone replacement therapy.

METHODS

A total of 2026 frozen blastocyst transfer cycles in the assisted reproductive center of northwest women and children's hospital from January, 2017, to August, 2020, were retrospectively analyzed. All the cycles were allocated into 3 groups according to the duration of estrogen administration: group A, 11-14 days (n = 346); group B, 15-18 days (n = 1191), and group C, ≥ 19 days (n = 489). Baseline data, clinical, and perinatal outcomes of the three groups were compared. A multivariate regression model was constructed to analyze the association between duration of estradiol administration and clinical outcomes.

RESULTS

We did not observe a significant association between duration of estrogen supplementation and LBR in group B (adjusted odds ratio [aOR] 1.14; 95% confidence interval [CI], 0.89-1.45) or group C (aOR 1.16; 95% CI, 0.86-1.56) patients with group A as the reference group, through logistic regression analysis. No statistical differences were observed in perinatal outcomes among the three groups.

CONCLUSION

The duration of estrogen administration was not associated with the likelihood of live birth in women undergoing frozen-thawed autologous single-blastocyst transfer.

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.

Effect of transdermal estrogen dose regimen for endometrial preparation of frozen-thawed embryo transfer on reproductive and obstetric outcomes

PURPOSE

Previous studies have reported different methods of estrogen administration during endometrial preparation for frozen-thawed embryo transfer (FET). This study aimed to investigate a beneficial regimen of transdermal estrogen administration for FET.

METHODS

We investigated the reproductive and obstetric outcomes of FET by comparing the increasing dose (ID) group that mimics changes in serum estradiol during the menstrual cycle and the constant dose (CD) group. Transdermal patches were used for estrogen administration in both groups. In our hospital, we targeted 315 cycles of the ID group in which FET was performed in 2017 and 324 cycles of the CD group in which FET was performed in 2018. In all cases, single embryo transfer was performed.

RESULTS

All were singleton pregnancies. There was no difference in clinical pregnancy rate (28.9% vs 28.2%, P =.837) and live birth rate (17.3% vs 21.4%, P =.201) between the ID and CD groups. Spontaneous abortion rate was significantly lower in the CD group than in the ID group (37.2% vs 23.0%, P =.041). There was no difference in obstetrical outcomes.

CONCLUSIONS

It was considered that the simple CD regimen may be more beneficial than the complicated ID regimen.

Investigating the impact of different strategies for endometrial preparation in frozen cycles considering normal responders undergoing IVF/ICSI cycles: a multicenter retrospective cohort study

Uncertainty exists concerning the type, adjunct, or dose of regimen to offer in frozen cycles in infertile women undergoing IVF/ICSI. Current systematic reviews have failed to identify one method of endometrial preparation as being more effective than another, whereas many IVF Units use variable and mixed protocols mainly based on their experience and convenience of use. Thus, we performed a four-center two-arm retrospective cohort study, encompassing 439 cycles in 311 women. The modalities analyzed were: Modified natural cycle without and with luteal support (Groups 1,2) and Hormone Replacement cycle (HRC) with and without GnRHa suppression (Groups 3,4). Various schemes of progesterone and estradiol were used and compared. χ² tests for categorical data and t-tests for continuous data were employed, stratifying by exposure, along with univariate and multivariable Logistic Regression models and subgroup analyses, according to the number of embryos transferred (1 vs. ≥2) and day of transfer (d2 vs. d5). Group 3 presented with statistically significant higher live birth and miscarriage rates in comparison to Group 4 (RR = 5.87, 95%CI: 2.44-14.14 and RR = 0.19, 95%CI: 0.06-0.60, respectively), findings that persisted in subgroup analyses according to the day of transfer and the number of embryos transferred. Progesterone administration through the combination of vaginal tabs and gel was associated with lower clinical pregnancy rates when compared to tabs (RR = 0.19, 95%CI: 0.05-0.71). The stable estrogen protocol compared to increasing estrogen at day 5 was associated with a higher positive hCG test and clinical pregnancy rate, while the progesterone through vaginal tabs was linked with lower miscarriages compared either with gel or combinations. In conclusion, HRC with GnRHa appears to be superior to HRC without GnRHa, concerning live birth and miscarriage, especially when the number of embryos transferred are ≥2 and irrespective of day of transfer. The use of progesterone vaginal tabs compared to gel or combinations is associated with better outcomes. Age is a significant predictor of a negative hCG test and clinical pregnancy rates. A properly conducted RCT is needed to evaluate the optimal frozen embryo transfer preparation strategy.Abbreviations: SD: standard deviation; BMI: body mass index; PCOS: polycystic ovarian syndrome; IQR: interquartile range; FSH: follicle-stimulating hormone; LH: luteinizing hormone; TSH: thyroid-stimulating hormone.

Oral dydrogesterone vs. micronized vaginal progesterone gel for luteal phase support in frozen-thawed single blastocyst transfer in good prognosis patients

OBJECTIVE

To investigate the efficacy of oral dydrogesterone for luteal phase support (LPS) in modified natural cycle frozen-thawed embryo transfers (mNC-FET) compared to micronized vaginal progesterone (MVP) gel.

METHODS

This was a randomized, single-center, parallel controlled trial conducted at an ART and Reproductive Genetics Centre within a private hospital between January and August 2019. A total of 134 women, aged below 38, were assigned randomly to receive oral dydrogesterone (n=67) or MVP (n=67) for LPS in mNC-FET. The primary outcome was ongoing pregnancy rate (OPR) and secondary outcomes were clinical pregnancy and miscarriage rates, patients' satisfaction and tolerability of oral and vaginal progesterone. A questionnaire was developed to compare patient satisfaction and side effect profiles.

RESULTS

There was no significant difference in demographic features such as female age, body mass index, AMH levels and fresh cycle characteristics between two groups (p>0.05). When mNC-FET outcomes were compared, OPR was 68.7 % in MVP gel group and 71.6 % in the dydrogesterone group respectively percentage difference, -2.99; 95 % CI: -17.96, 13.10) Biochemical and clinical pregnancy rates and biochemical and clinical miscarriage rates were also similar between two groups. A significantly higher patient tolerability score was present in the dydrogesterone arm (4.09 ± 0.96 vs 3.36 ± 1.23, p=0.001).

CONCLUSION

Our results suggest that oral dydrogesterone provides similar ongoing pregnancy rates compared to MVP gel as a LPS in mNC FET. Since dydrogesterone is an effective and easy-to-use option with fewer intolerable side effects including vaginal irritation, vaginal discharge, and preventing sexual intercourse, it can be used as LPS in mNC FET.

Endometrial preparation for women undergoing embryo transfer with frozen embryos or embryos derived from donor oocytes

BACKGROUND

A frozen embryo transfer (FET) cycle is when one or more embryos (frozen during a previous treatment cycle) are thawed and transferred to the uterus. Some women undergo fresh embryo transfer (ET) cycles with embryos derived from donated oocytes. In both situations, the endometrium is primed with oestrogen and progestogen in different doses and routes of administration.

OBJECTIVES

To evaluate the most effective endometrial preparation for women undergoing transfer with frozen embryos or embryos from donor oocytes with regard to the subsequent live birth rate (LBR).

SEARCH METHODS

The Cochrane Gynaecology and Fertility Group trials register, CENTRAL, MEDLINE, Embase, PsycINFO, LILACS, trials registers and abstracts of reproductive societies' meetings were searched in June 2020 together with reference checking and contact with study authors and experts in the field to identify additional studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) evaluating endometrial preparation in women undergoing fresh donor cycles and frozen embryo transfers.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. We analysed all available interventions versus placebo, no treatment, or between each other. The primary review outcome was live birth rate. Secondary outcomes were clinical and multiple pregnancy, miscarriage, cycle cancellation, endometrial thickness and adverse effects.

MAIN RESULTS

Thirty-one RCTs (5426 women) were included. Evidence was moderate to very low-quality: the main limitations were serious risk of bias due to poor reporting of methods, and serious imprecision. Stimulated versus programmed cycle We are uncertain whether a letrozole-stimulated cycle compared to a programmed cycle, for endometrial preparation, improves LBR (odds ratio (OR) 1.26, 95% confidence interval (CI) 0.49 to 3.26; 100 participants; one study; very low-quality evidence). Stimulating with follicle stimulating hormone (FSH), letrozole or clomiphene citrate may improve clinical pregnancy rate (CPR) (OR 1.63, 95% CI 1.12 to 2.38; 656 participants; five studies; I² = 11%; low-quality evidence). We are uncertain if they reduce miscarriage rate (MR) (OR 0.79, 95% CI 0.36 to 1.71; 355 participants; three studies; I² = 0%; very low-quality evidence). Endometrial thickness (ET) may be reduced with clomiphene citrate (mean difference(MD) -1.04, 95% CI -1.59 to -0.49; 92 participants; one study; low-quality evidence). Other outcomes were not reported. Natural versus programmed cycle We are uncertain of the effect from a natural versus programmed cycle for LBR (OR 0.97, 95% CI 0.74 to 1.28; 1285 participants; four studies; I² = 0%; very low-quality evidence) and CPR (OR 0.79, 95% CI 0.62 to 1.01; 1249 participants; five studies; I² = 60%; very low-quality evidence), while a natural cycle probably reduces the cycle cancellation rate (CCR) (OR 0.60, 95% CI 0.44 to 0.82; 734 participants; one study; moderate-quality evidence). We are uncertain of the effect on MR and ET. No study reported other outcomes. Transdermal versus oral oestrogens From low-quality evidence we are uncertain of the effect transdermal compared to oral oestrogens has on CPR (OR 0.86, 95% CI 0.59 to 1.25; 504 participants; three studies; I² = 58%) or MR (OR 0.55, 95% CI 0.27 to 1.09; 414 participants; two studies; I² = 0%). Other outcomes were not reported. Day of starting administration of progestogen When doing a fresh ET using donated oocytes in a synchronised cycle starting progestogen on the day of oocyte pick-up (OPU) or the day after OPU, in comparison with recipients that start progestogen the day prior to OPU, probably increases the CPR (OR 1.87, 95% CI 1.13 to 3.08; 282 participants; one study, moderate-quality evidence). We are uncertain of the effect on multiple pregnancy rate (MPR) or MR. It probably reduces the CCR (OR 0.28, 95% CI 0.11 to 0.74; 282 participants; one study; moderate-quality evidence). No study reported other outcomes. Gonadotropin-releasing hormone (GnRH) agonist versus control A cycle with GnRH agonist compared to without may improve LBR (OR 2.62, 95% CI 1.19 to 5.78; 234 participants; one study; low-quality evidence). From low-quality evidence we are uncertain of the effect on CPR (OR 1.08, 95% CI 0.82 to 1.43; 1289 participants; eight studies; I² = 20%), MR (OR 0.85, 95% CI 0.36 to 2.00; 828 participants; four studies; I² = 0%), CCR (OR 0.49, 95% CI 0.21 to 1.17; 530 participants; two studies; I² = 0%) and ET (MD -0.08, 95% CI -0.33 to 0.16; 697 participants; four studies; I² = 4%). No study reported other outcomes. Among different GnRH agonists From very low-quality evidence we are uncertain if cycles among different GnRH agonists improves CPR or MR. No study reported other outcomes. GnRH agonists versus GnRH antagonists GnRH antagonists compared to agonists probably improves CPR (OR 0.62, 95% CI 0.42 to 0.90; 473 participants; one study; moderate-quality evidence). We are uncertain of the effect on MR and MPR. No study reported other outcomes. Aspirin versus control From very low-quality evidence we are uncertain whether a cycle with aspirin versus without improves LBR, CPR, or ET. Steroids versus control From very low-quality evidence we are uncertain whether a cycle with steroids compared to without improves LBR, CPR or MR. No study reported other outcomes.

AUTHORS' CONCLUSIONS

There is insufficient evidence on the use of any particular intervention for endometrial preparation in women undergoing fresh donor cycles and frozen embryo transfers. In frozen embryo transfers, low-quality evidence showed that clinical pregnancy rates may be improved in a stimulated cycle compared to a programmed one, and we are uncertain of the effect when comparing a programmed cycle to a natural cycle. Cycle cancellation rates are probably reduced in a natural cycle. Although administering a GnRH agonist, compared to without, may improve live birth rates, clinical pregnancy rates will probably be improved in a GnRH antagonist cycle over an agonist cycle. In fresh synchronised oocyte donor cycles, the clinical pregnancy rate is probably improved and cycle cancellation rates are probably reduced when starting progestogen the day of or day after donor oocyte retrieval. Adequately powered studies are needed to evaluate each treatment more accurately.

Is there a critical LH level for hCG trigger after the detection of LH surge in modified natural frozen-thawed single blastocyst transfer cycles?

Purpose

There is no consensus yet in the literature on an optimal luteinizing hormone (LH) level for human chorionic gonadotrophin (hCG) trigger timing in patients undergoing frozen-thawed embryo transfer (FET) with modified natural cycles (mNC). The objective of our study was to compare the clinical results of hCG trigger at different LH levels in mNC-FET cases.

Methods

This retrospective study was conducted in Istanbul Memorial Hospital ART and Genetics Center. A total of 1076 cases with 1163 mNC-FET cycles were evaluated. LH levels between the start of LH rise (15 IU/L) and LH peak level (> 40 IU/L) were evaluated. Cycles were analyzed in four groups: group A (n = 287) LH level on the day prior to the day of hCG; groups B, C and D, LH levels on the day of hCG: group B (n = 245) LH 15–24.9; group C (n = 253), LH 25–39.9; group D (n = 383) LH ≥ 40. Cycle outcomes in the four groups were compared.

Results

Subgroup analyses of mNC-FET groups showed that implantation, clinical and ongoing pregnancy rates, and pregnancy losses were not significantly different in patients with different LH levels on the day of hCG trigger.

Conclusion

Our study suggests that hCG can be administered at any time between the start of LH rise (≥ 15 IU/L) and LH peak level (≥ 40 IU/L) without a detrimental effect on clinical outcome.

The effect of intrauterine insemination preceding frozen-thawed elective single embryo transfer in couples with unexplained subfertility

Introduction

This prospective randomized controlled trial aimed to evaluate the effect of intrauterine insemination (IUI) before frozen-thawed elective single embryo transfer (FT-eSET).

Material and methods

A total of 200 couples with unexplained subfertility underwent in-vitro fertilization (IVF) treatment. Patients were randomly assigned to either FT-eSET or IUI preceding FT-eSET. Both groups were composed of 100 women. IUI was timed 6 days before FT-eSET in the IUI preceding FT-eSET group. Implantation rates (IR), biochemical and clinical abortion rates (AR), clinical pregnancy rates (PR), ongoing pregnancy rates (PRs), and live birth rates were measured in this study.

Results

The IUI preceding FT-eSET group was associated with higher rates of clinical pregnancy, 54% vs. 42%, but not significantly. Similarly, IR, PR and live birth rate were higher in the IUI preceding FT-eSET group but not significantly. In the IUI preceding FT-eSET group, the biochemical and clinical abortion rates were lower than in the control group (9.5% vs. 14.2% and 5.5% vs. 5.2%, respectively). However, no statistically significant difference was found between the two groups, either.

Conclusions

This is the first study showing that IUI may precede FT-eSET to improve PR in couples with unexplained subfertility. Also, performing IUI before FT-eSET may decrease biochemical and clinical abortion rates.

Endometrial preparation for frozen-thawed embryo transfer in an artificial cycle: transdermal versus vaginal estrogen

The objective was to compare the endometrial thickness (ET) in a frozen embryo transfer (FET) cycle between transdermal and vaginal estrogen. Our secondary objectives were to compare the patient satisfaction and the pregnancy outcomes. Prospective monocentric cohort study between 01/2017 and 12/2017 at a single institution. Choice of administration was left to the patient. 119 cycles had transdermal estrogen (T-group) and 199 had vaginal estrogen (V-group). The ET at 10 ± 1 days of treatment was significantly higher in the T-group compared to the V-group (9.9 vs 9.3 mm, p = 0.03). In the T-group, the mean duration of treatment was shorter (13.6 vs 15.5 days, p < 0.001). The rate of cycle cancelation was comparable between the two groups (12.6% vs 8.5%, p = 0.24). Serum estradiol levels were significantly lower (268 vs 1332 pg/ml, p < 0.001), and serum LH levels were significantly higher (12.1 ± 16.5 vs 5 ± 7.5 mIU/ml, p < 0.001) in the T-group. Patient satisfaction was higher in the T-group (p = 0.04) and 85.7% (36/42) of women who had received both treatments preferred the transdermal over the vaginal route. Live birth rates were comparable between the two groups (18% vs 19%, p = 0.1). Transdermal estrogen in artificial FET cycles was associated with higher ET, shorter treatment duration and better tolerance.