Effect of luteal phase support with vaginal progesterone on pregnancy outcomes in natural frozen embryo transfer cycles: A meta-analysis

Progesterone concentrations on blastocyst transfer day in modified natural cycle frozen embryo transfer cycles

RESEARCH QUESTION

Are serum progesterone concentrations on the day of modified natural cycle (mNC) frozen blastocyst transfer (FET) without luteal phase support (LPS) associated with clinical pregnancy rate (CPR)?

DESIGN

Data were collected between January 2019 and October 2022 as a sub-study of an ongoing randomized controlled trial assessing pregnancy outcomes in mNC-FET. The sub-study included all women (n = 209) randomized to mNC-FET without LPS at the time of data extraction. Participants were aged 18-41 years, had regular menstrual cycles and underwent mNC-FET treatment with single-blastocyst transfer. Associations between the serum progesterone concentration on the day of blastocyst transfer and CPR, pregnancy rate and pregnancy loss rate (PLR) were examined between groups with low and higher progesterone concentrations using the 25th and 10th percentiles as cut-offs. Multivariate logistic regression analyses were performed to adjust for potential confounding factors.

RESULTS

Progesterone concentrations on the day of blastocyst transfer in mNC-FET without LPS ranged from 4.9 to 91.8 nmol/l, with the 25th and 10th percentiles at 29.0 nmol/l and 22.5 nmol/l, respectively. Serum progesterone concentrations did not differ between women with or without a clinical pregnancy (mean [SD] 38.5 [14.0] versus 36.8 [12.4] nmol/l; P = 0.350). Furthermore, the CPR, pregancy rate and PLR were similar in women with low or high progesterone concentrations when using the 25th or the 10th progesterone percentile as cut-off. Multivariate regression analyses showed no association between progesterone concentrations and CPR.

CONCLUSIONS

No association was found between progesterone concentration on the day of blastocyst transfer and pregnancy outcome in women undergoing mNC-FET without progesterone LPS.

Clinical Outcomes in Hormone Replacement Therapy (HRT)-Frozen Embryo Transfer (FET) Protocol Increased by Administering Gonadotropin-Releasing Hormone Agonist (GnRH) in the Initial Stage of the Luteal Phase: A Retrospective Analysis

OBJECTIVE

The objective of this study was to determine if gonadotropin-releasing hormone agonist (GnRH) administration supporting the luteal phase in frozen embryo transfer (FET) improves clinical outcomes Methods and materials This is a retrospective cohort study and we analyzed 3515 cycles of FET at the Department of Reproductive Medicine in our hospital from February 2018 through December 2021. Patients were divided into the GnRH (triptorelin+progesterone and human chorionic gonadotropin (hCG)) group and the non-GnRHa (existing treatment without triptorelin) group. There were 1033 and 2485 cases in the above groups, respectively. Live birth rates (LBR) and clinical pregnancy rates (CPR) were contrasted in the two groups.

RESULTS

We found greater CPR (58.00% versus 48.40%, P-value = 0.003) and LBR (52.70% versus 45.60%, P-value = 0.001) for HRT-FET cycles, and found no clinical significance for natural cycle FET (NC-FET) (58.20% versus 52.90%, P-value = 0.364 and 54.40% versus 47.00%, P-value=0.211), GnRH+HRT-FET (53.00% versus 53.00%, P-value=0.176 and 46.20% versus 47.30%, P-value=0.794), and stimulation-FET (59.30% versus 52.90%, P-value=.00.566 and 59.30% versus 47.10%, P-value=.00.247) in terms of CPR and LBR in the two groups. There was a 47% increase in CPR in the GnRH group, and there was a 33% increase in LBR in the same group.

CONCLUSION

During HRT-FET cycles, administering triptorelin three to four times in the existing luteal support can improve CPR and LBR, and administering triptorelin during the initial stage of the luteal phase can prove a new option for luteal support.

Initiating luteal phase support with sc progesterone based on low serum progesterone on the transfer day in true natural cycle frozen embryo transfers

Introduction

Concerning contemporary in-vitro fertilisation (IVF) practice, the use of frozen embryo transfer (FET) cycles has become more common than fresh transfers. Natural cycle (NC), programmed artificial cycle and mild stimulation cycle are primary endometrium preparation cycles. Monitoring serum progesterone levels in FET cycles are in the scope of current research focus. Low progesterone levels on the day of embryo transfer is presumed to negatively affect pregnancy outcomes, while progesterone supplementation may improve pregnancy rates. The purpose of our trial is to evaluate whether initiating subcutaneous (SC) progesterone supplementation on the day of embryo transfer when serum progesterone levels are below 10 ng/mL in tNC-FET will result in pregnancy rates comparable to those of patients with sufficient serum progesterone.

Methods

Retrospective single centre study was conducted between August 2022 and April 2023 with 181 tNC-FETs. Patients were separated into groups according to serum progesterone concentrations (≥10 ng/mL and <10 ng/mL) on embryo transfer (ET) day. S.c progesterone (25 mg) was given on the day of ET when serum progesterone was <10 ng/mL, continuing until the 10th gestational week. Blood samples for pregnancy tests were collected 12 days after ET. Outcome parameters were pregnancy rate, clinical pregnancy rate (CPR), miscarriage rate, multiple pregnancy rate, biochemical pregnancy, and ongoing pregnancy rate (OPR).

Results

About half (49.7%) had adequate progesterone concentrations (≥10ng/mL) on ET day. There was no significant difference between the groups regarding positive pregnancy test, OPR, multiple pregnancies, and miscarriage rates (57.8% versus 52.7%; 34.4% versus 29.7%, 1.1% versus 2.2%; 7.8% versus 5.5%; respectively, for progesterone concentrations on ET day ≥10 ng/mL and <10 ng/mL). With 55.2% of transfers leading to clinical pregnancy, significant differences emerged in biochemical pregnancy and CPR (3.3% vs 12.1%, P=0.02; 54.4% vs 40.7%, P=0.03, for ≥10 ng/mL and <10 ng/mL progesterone concentrations on ET day).

Discussion

This study indicates that nearly half of the tNC-FETs may need luteal phase support due to low progesterone. However, 25 mc sc progesterone rescued the luteal support and yielded similar OPR as compared to normal progesterone group. Further studies are needed for understanding optimal progesterone levels, supplementation effectiveness, and potential benefits of earlier supplementation in FETs.

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.

Impact of progesterone-free luteal phase support following natural cycle frozen embryo transfer: Study protocol for a multicenter, non-inferiority, randomized controlled trial

Introduction

Nowadays, frozen-thawed embryo transfer (FET) has become one of the standard treatments for infertility in the field of assisted reproductive technology (ART). Natural cycle FET (NC-FET) has many advantages, such as simplicity and economics, no effect on patients’ menstrual cycles, estrogen and progesterone levels, as well as no interference in endometrial growth and transformation, which is aligned with the natural physiological state of embryo implantation. Nonetheless, there is a controversy regarding the need for luteal phase support (LPS) during NC-FET cycles. The purpose of this study is to assess whether LPS was not inferior to non-LPS in terms of OPR in NC-FET cycles.

Methods and analysis

This study including 1,010 ovulatory women undergoing in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles with an elective freeze-all strategy followed by NC-FET will be performed at four university-affiliated reproductive centers. Participants will be randomly assigned in a 1:1 ratio to receive LPS treatment or not. This study is designed as an open-label, non-inferiority, randomized controlled trial (RCT), and the primary statistical strategies were intention-to-treat (ITT) and per-protocol (PP) analysis.

Discussion

There may not have been any significant difference in the chance of a live birth after FET if no progesterone was supplemental during the luteal phase. However, due to the limited number of previous studies, which are mainly retrospective, evidence is still limited. Thus, by conducting this multicenter RCT, we intend to evaluate whether LPS is necessary in NC-FET.

Ethics and dissemination

A Reproductive Ethics Committee of the Affiliated Hospital of Shandong University of Traditional Chinese Medicine (SDUTCM) has approved this study. This study will handle the data as required by general data protection regulations. Participants will sign a written informed consent regarding participation in the study and storage of blood samples in a biobank for future research. This study will be monitored by study personnel trained in Good Clinical Practice who are not involved in the study. The results of this study will be disseminated through publication in international peer-reviewed scientific journals.

Clinical trial registration

[https://www.chictr.org.cn/], identifier [ChiCTR2200057498].

Progesterone supplementation in natural cycles improves live birth rates after embryo transfer of frozen-thawed embryos-a randomized controlled trial

STUDY QUESTION

Does supplementation with vaginal tablets of progesterone after frozen-thawed embryo transfer in natural cycles improve the live birth rate?

SUMMARY ANSWER

Supplementation with vaginal tablets of progesterone after frozen-thawed embryo transfer in natural cycles significantly improves the number of live births.

WHAT IS KNOWN ALREADY

Progesterone supplementation during luteal phase and early pregnancy may improve the number of live births after frozen-thawed embryo transfer. However, due to the limited number of previous studies, being mainly retrospective, evidence is still limited.

STUDY DESIGN, SIZE, DURATION

This is a prospective randomized controlled trial, performed at two university clinics. In total, 500 subjects were randomized with a 1:1 allocation into two groups, during the period February 2013 to March 2018. Randomization was performed after a frozen embryo transfer in a natural cycle by use of opaque sealed envelopes. The primary outcome was live birth rate; secondary outcomes were pregnancy, biochemical pregnancy, clinical pregnancy and miscarriage rate, and if there was a possible association between the serum progesterone concentration on the day of embryo transfer and live birth rate.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women, receiving embryo transfer in natural cycles participated in the study. The embryos were frozen on Day 2, 3, 5 or 6. In total, 672 women having regular menstrual cycles were invited to participate in the study; of those, 500 agreed to participate and 488 were finally included in the study. Half of the study subjects received progesterone supplementation with progesterone vaginal tablets, 100 mg twice daily, starting from the day of embryo transfer. The other half of the subjects were not given any treatment. Blood samples for serum progesterone measurements were collected from all subjects on the day of embryo transfer.

MAIN RESULTS AND THE ROLE OF CHANCE

There were no differences in background characteristics between the study groups. In the progesterone supplemented group, 83 of 243 patients (34.2%) had a live birth, compared to 59 of 245 patients (24.1%) in the control group (odds ratio 1.635, 95% CI 1.102–2.428, P = 0.017*). The number of pregnancies was 104 of 243 (42.8%) and 83 of 245 (33.9%), respectively (odds ratio 1.465, 95% CI 1.012–2.108, P = 0.049*) and the number of clinical pregnancies was 91 of 243 (37.4%) and 70 of 245 (28.6%), respectively (odds ratio 1.497, 95% CI 1.024–2.188, P = 0.043*). There were no significant differences in biochemical pregnancy rate or miscarriage rate. There was no correlation between outcome and serum progesterone concentration.

LIMITATIONS, REASONS FOR CAUTION

The study was not blinded because placebo tablets were not available. Supplementation started on embryo transfer day, regardless of the age of the embryos, which resulted in a shorter supplementation time for Day 5/6 embryos compared to Day 2/3 embryos.

WIDER IMPLICATIONS OF THE FINDINGS

Supplementation with progesterone in natural cycles improved the number of live births after frozen-thawed embryo transfer and should therefore be considered for introduction in clinical routine.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by Uppsala University, the Uppsala-Family Planning Foundation, and Ferring Pharmaceuticals AB, Malmö, Sweden. The authors have no personal conflicting interests to declare.

TRIAL REGISTRATION NUMBER

NL4152.

TRIAL REGISTRATION DATE

5 December 2013.

DATE OF FIRST PATIENT’S ENROLMENT

18 February 2013.

Vaginal progesterone as luteal phase support in natural cycle frozen-thawed embryo transfer (ProFET): protocol for a multicentre, open-label, randomised controlled trial

INTRODUCTION

Vaginal progesterone supplementation is frequently given to patients receiving frozen embryo transfer (FET) in the natural cycle aiming to increase the chance of pregnancy and live birth. To date, only a few studies have investigated if progesterone supplementation is beneficial in these cycles and the level of evidence for progesterone supplementation is very low.

METHODS AND ANALYSIS

The ProFET trial is a multicentre, open-label, randomised controlled trial powered for this investigation, including 1800 women with regular menstrual cycles (24-35 days), aged 18-43 years planned for natural cycle-FET receiving a single blastocyst for transfer. Participants are randomised (1:1:1) to either luteal phase progesterone for 3 weeks, luteal phase progesterone for 7 weeks or no luteal phase progesterone. The participating study centres consist of 12 in vitro fertilisation-clinics in Sweden and 1 in Iceland. The primary outcome is to investigate if luteal phase support (LPS) by vaginal progesterone increases the chance of a live birth per randomised patient in a natural FET cycle compared with no LPS.

ETHICS AND DISSEMINATION

The trial was approved by the Swedish Ethical Review Authority (ID 2020-06774, 2021-02822 and 2022-01502-02) and the Swedish Medical Products Agency (ID nr 5.1-2020-102613). All participants are required to provide written informed consent. The outcome of this study will be disseminated to the public through broadcasts, newspapers and presentations at scientific congresses as well as publications in international scientific journals.

TRIAL REGISTRATION NUMBER

NCT04725864.

Should women receive luteal support following natural cycle frozen embryo transfer? A systematic review and meta-analysis

BACKGROUND

Spontaneous ovulation during a natural menstrual cycle is frequently used for timing frozen embryo transfer (FET). Nevertheless, it remains unclear whether or not women should receive luteal phase support (LPS) following natural cycle frozen embryo transfer (NC-FET).

OBJECTIVE AND RATIONALE

The aim of this systematic review and meta-analysis was to study whether the administration of LPS improves the reproductive outcome following NC-FET.

SEARCH METHODS

We conducted a systematic search of the literature published in Medline/PubMed, Embase and the Cochrane Library, from January 2000 until December 2020. We included all original English, peer-reviewed articles, irrespective of the study design. The search strategy included keywords related to NC-FET and luteal phase support. Studies reporting the results of artificial or stimulated FET cycles were excluded.

OUTCOMES

Our systematic search generated 416 records. After screening, eight studies were included in the review and seven studies were included in the meta-analysis. Two studies (n = 858) used hCG and six studies (n = 1507) used progesterone for luteal support. Four studies were randomised controlled trials (RCTs), whereas the other four were historic cohort studies. In a meta-analysis using a random effects model, hCG administration for LPS did not increase the clinical pregnancy rate (CPR) (two studies, odds ratio (OR) 0.85, 95% CI 0.64-1.14). On the other hand, progesterone LPS was associated with a higher CPR (five studies, OR 1.48, 95% CI 1.14-1.94), and a higher live birth rate (LBR) (three studies, OR 1.67, 95% CI 1.19-2.36). The association between progesterone LPS and the LBR remained significant after excluding non-randomised studies.

WIDER IMPLICATIONS

The available evidence indicates that progesterone administration for LPS is beneficial following NC-FET. There is no evidence to support the administration of hCG for LPS in these cases. Additional large RCTs are necessary to improve the quality of evidence and validate our findings.

The clinical relevance of luteal phase progesterone support in true natural cycle cryopreserved blastocyst stage embryo transfers: a retrospective cohort study

Background

More than 67% of all embryos transferred in the United States involve frozen-thawed embryos. Progesterone supplementation is necessary in medicated cycles to luteinize the endometrium and prepare it for implantation, but little data is available to show if this is beneficial in true natural cycles. We evaluated the use of luteal phase progesterone supplementation for cryopreserved/warmed blastocyst transfers in true natural cycles not using an ovulatory trigger.

Methods

Retrospective cohort study in a single academic medical center. We studied the use of luteal phase progesterone supplementation in patients undergoing true natural cycle cryopreserved blastocyst embryo transfers. Our primary outcome measure was ongoing pregnancy rate, with other pregnancy outcomes being evaluated (i.e. implantation rate, miscarriage rate, ectopic rate, and multifetal gestation). Categorical data were analyzed utilizing Fisher’s exact test and all binary variables were analyzed using log-binomial regression to produce a risk ratio.

Results

Two hundred twenty-nine patients were included in the analysis with 149 receiving luteal phase progesterone supplementation and 80 receiving no luteal phase support. Patient demographic and cycle characteristics, and embryo quality were similar between the two groups. No difference was seen in ongoing pregnancy rate (49.0% vs. 47.5%, p = 0.8738), clinical pregnancy rate (50.3% vs. 47.5%, p = 0.7483), positive HCG rate (62.4% vs. 57.5%, p = 0.5965), miscarriage/abortion rate (5.4% vs. 2.5%, p = 0.2622), ectopic pregnancy rate (0% vs. 1.3%, p = 0.3493), or multifetal gestations (7.4% vs. 3.8%, p = 0.3166).

Conclusion(s)

The addition of luteal phase progesterone support in true natural cycle cryopreserved blastocyst embryo transfers did not improve pregnancy outcomes and therefore the routine use in practice cannot be recommended based on this study, but the utilization should not be discouraged without further studies.

Capsule

Progesterone supplementation as luteal phase support in true natural cycle cryopreserved blastocyst transfers does not improve ongoing pregnancies.