Endometrial preparation for vitrified-warmed embryo transfer with or without GnRH-agonist pre-treatment in patients with polycystic ovary syndrome: a randomized controlled trial

Vasodilators for women undergoing fertility treatment

BACKGROUND

The rate of successful pregnancies brought to term has barely increased since the first assisted reproductive technology (ART) technique became available. Research suggests that vasodilators may increase endometrial receptivity, thicken the endometrium, and favour uterine relaxation, all of which could improve the chances of successful assisted pregnancy.

OBJECTIVES

To evaluate the effectiveness and safety of vasodilators in women undergoing fertility treatment.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group Specialised Register of controlled trials, CENTRAL, MEDLINE, Embase, three other databases, and two clinical trial registries in April 2024, with no language or date restrictions. We also searched grey literature sources and checked the reference lists of relevant articles.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing vasodilators (alone or combined with other treatments) versus placebo or no treatment or versus other agents in women undergoing fertility treatment.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed risk of bias, extracted data, and calculated risk ratios (RRs). We combined study data using a fixed-effect model and assessed evidence certainty using the GRADE approach. Our primary outcomes were live birth or ongoing pregnancy and vasodilator side effects. Our secondary outcomes were clinical pregnancy, endometrial thickness, multiple gestation, miscarriage, and ectopic pregnancy.

MAIN RESULTS

We included 45 studies with a total of 4404 women. The included studies compared a vasodilator versus a placebo or no treatment (40 RCTs), vasodilators plus another agent versus placebo or no treatment (3 RCTs) or versus oestrogens (3 RCTs). The mean length of follow-up was 15.45 weeks. Overall, the certainty of evidence was very low to moderate. The main limitations were imprecision (low number of events and participants) and risk of bias (lack of blinding in studies that reported subjective outcomes). Vasodilators versus placebo or no treatment Vasodilators may result in little to no difference in rates of live birth or ongoing pregnancy compared with placebo or no treatment (RR 1.21, 95% CI 0.93 to 1.58; I² = 0%; 6 RCTs, 740 women; low-certainty evidence), but probably increase overall rates of side effects (RR 2.14, 95% CI 1.55 to 2.98; I² = 0%; 7 RCTs, 668 women; moderate-certainty evidence). The evidence suggests that 246 per 1000 women achieve live birth or ongoing pregnancy with a placebo or no treatment, and 229 to 389 per 1000 will do so using vasodilators. Vasodilators compared with placebo or no treatment likely increase rates of clinical pregnancy (RR 1.45, 95% CI 1.28 to 1.64; I² = 22%; 25 RCTs, 2506 women; moderate-certainty evidence). Vasodilators compared with placebo or no treatment probably have little or no effect on rates of multiple gestation or birth (RR 1.37, 95% CI 0.73 to 2.55; I² = 0%; 7 RCTs, 763 women; moderate-certainty evidence), miscarriage (RR 1.01, 95% CI 0.59 to 1.74; I² = 0%; 8 RCTs; 829 women; moderate-certainty evidence), and ectopic pregnancy (RR 1.25, 95% CI 0.34 to 4.59; I² = 0%; 4 RCTs, 543 women; moderate-certainty evidence). Most studies found a beneficial effect of vasodilators for endometrial thickness, but the reported effect estimates varied (I² = 93%), from a mean difference of 0.47 mm higher (95% CI 0.90 mm lower to 1. 84 mm higher) to 1.94 mm higher (95% CI 1.37 higher to 2.51 mm higher), and the evidence was very uncertain. Hence, we are unsure how to interpret these results. Vasodilators versus oestrogens Vasodilators compared with oestrogens may have little or no effect on rates of live birth or ongoing pregnancy (RR 0.83, 95% CI 0.30 to 1.33; 1 RCT, 44 women, low-certainty evidence). The evidence is very uncertain regarding the effect of sildenafil compared with oestrogens on clinical pregnancy rates (RR 0.99, 95% CI 0.71 to 1.38; I² = 59%; 3 RCTs, 262 women; very low-certainty evidence), endometrial thickness (RR 1.90, 95 CI 1.15 to 3.13; 1 RCT, 120 women; very low-certainty evidence) and miscarriage rates (RR 0.50, 95% CI 0.05 to 5.12; 1 RCT, 44 women; very low-certainty evidence) AUTHORS' CONCLUSIONS: Among women undergoing fertility treatment, there may be little or no difference in the rate of live birth or ongoing pregnancy in those who receive vasodilators compared with those who receive a placebo or no treatment, and compared with those who receive oestrogens. Compared with placebo or no treatment, vasodilators likely increase rates of clinical pregnancy, but probably also increase overall rates of side effects. The evidence on clinical pregnancy with vasodilators versus oestrogens is very uncertain, and we found no evidence on overall side effects for the comparison of vasodilators versus oestrogens. We are unsure about the effect of vasodilators versus placebo or no treatment and versus oestrogens on endometrial thickness. Vasodilators versus placebo or no treatment probably have little or no effect on multiple gestation or birth, miscarriage, and ectopic pregnancy. Future studies should be adequately randomised and powered to ensure a more accurate evaluation of each treatment, with live births as a primary outcome.

Improving reproductive outcomes in frozen embryo transfer over fresh embryo transfer in women with endometrioma: A historical cohort study

Background

Endometrioma, a common manifestation of endometriosis, often indicates the severity of the disease. In vitro fertilization and embryo transfer (ET) are key therapeutic strategies for infertility associated with endometriosis. However, the optimal type of ET (frozen or fresh) and its impact on pregnancy success rates remain debated, with limited studies available.

Objective

This historical cohort study aimed to compare fertility and neonatal outcomes, focusing on live birth rate (LBR), clinical pregnancy, and implantation rates in women with endometrioma-associated infertility, between fresh and frozen embryo transfer (FET).

Materials and Methods

In this historical cohort study, the medical records (files) of 289 women diagnosed with endometrioma-related infertility, who underwent in vitro fertilization/intracytoplasmic sperm injection treatment at Royan Institute, Tehran, Iran between March 2016-2021 were reviewed. Ultimately, 200 files that met the established criteria were selected for review. The extracted data was then compared between groups: FET (n = 121) and fresh ET (n = 79).

Results

No significant differences were observed between the groups in terms of demographic characteristics and endometrioma size. The only significant difference in fertility outcomes was the LBR, which was 36.4% for the FET group compared to 22.8% for the fresh ET group (p = 0.04). No significant differences were observed in neonatal outcomes between the groups. Overall, our study suggests that FET may lead to higher LBRs in women diagnosed with endometrioma.

Conclusion

Our study suggests that FET may lead to higher LBRs in women diagnosed with endometrioma.

GnRH agonist pretreatment for frozen embryo transfer among women with polycystic ovary syndrome: a narrow systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Frozen embryo transfer (FET) is usually recommended for women with polycystic ovary syndrome (PCOS) undergoing In vitro fertilization (IVF). While there is no consensus as to the optimal protocol of endometrial preparation for FET. The effect of gonadotropin-releasing hormone agonist (GnRH-a) pretreatment for FET among women with PCOS remains controversial.

PURPOSE

We intend to explore whether GnRH-a pretreatment could improve clinical outcomes for women with PCOS undergoing FET.

METHODS

PubMed, Embase, ClinicalTrials.gov, Cochrane Library, and Web of Science were searched up to May 16, 2024. Eligible studies involved patients with PCOS undergoing FET and receiving GnRH-a pretreatment for endometrial preparation, with artificial cycle (AC) as the control therapy. Only randomized controlled trials (RCTs) published in Chinese and English were included. Data extraction was performed independently by two authors. Effect was quantified using odd ratios (ORs) with 95% confidence intervals (CIs) using random-effect models with the Mantel-Hansel (M-H) method in Revman software. Quality of outcomes was evaluated using the GRADEpro system. Primary outcomes contained the clinical pregnancy rate, miscarriage rate, and live birth rate. Secondary outcomes included the incidence of preterm labor and gestational diabetes mellitus (GDM).

RESULTS

Ninety-seven records were initially retrieved, with 21 duplicates and 65 articles excluded after title and abstract screening. Seven studies were excluded due to retrospective design, leaving three RCTs with 709 participants. Among them, 353 received GnRH-a pretreatment as the intervention group and 356 received AC as the control group. No significant differences were observed in the clinical pregnancy rate (OR 1.09, 95% CI 0.75 to 1.56, P = 0.66), miscarriage rate (OR 0.73, 95% CI 0.28 to 1.90, P = 0.52), live birth rate (OR 0.87, 95% CI 0.61 to 1.25, P = 0.46), and the risk of preterm labor (OR 1.45, 95% CI 0.79 to 2.65, P = 0.23) and GDM (OR 0.73, 95% CI 0.37 to 1.48, P = 0.39) between the two groups.

CONCLUSIONS

In this meta-analysis, GnRH-a pretreatment does not confer any advantages and appears unnecessary for women with PCOS undergoing FET. Additional RCTs should focus on maternal complications and the health of offspring.

Pretreatment with or without GnRH-agonist before frozen-thawed embryo transfer in patients with PCOS: a systematic review and meta-analysis

PURPOSE

This study was aimed to systematically evaluate the efficacy of artificial cycle-prepared frozen-thawed embryo transfer (FET) with or without gonadotrophin-releasing hormone agonist (GnRH-a) pretreatment for women with polycystic ovary syndrome (PCOS).

METHODS

The analysis was carried out by searching the PubMed, EMBASE, and CNKI databases with a combination of keywords before October 2021. The available studies of the effects of GnRH-a pretreatment or no pretreatment on FET in PCOS patients were considered. The risk ratios (RRs) or standardized mean differences (SMD) with 95% confidence intervals (CIs) were calculated with using subgroups and sensitivity analysis. The quality evaluation for this analysis was followed.

RESULTS

Seventeen studies including 3646 women were analyzed. GnRH-a pretreatment was significantly associated with a higher implantation rate (RR = 1.12, 95%CI: 1.00-1.24) and clinical pregnancy rate (RR = 1.19, 95%CI: 1.08-1.32) than the placebo. Moreover, in the GnRH-a pretreatment group, significant differences were detected for increasing the endometrium thickness among PCOS patients (SMD = 0.56, 95%CI: 0.20-0.92). However, for RCTs subgroup, no differences were observed, even after sensitivity analyses. In addition, the miscarriage rates, ectopic pregnancy rates, multiple pregnancy rates, and live birth rates were similar in both two groups.

CONCLUSIONS

Endometrial preparation using GnRH agonist pretreatment prior to FET seems to be the better choice for PCOS patients. However, well-designed RCTs are required for confirmation.

Pituitary Suppression with Gonadotropin-Releasing Hormone Agonist Prior to Artificial Endometrial Preparation in Frozen-Thawed Embryo Transfer Cycles: A Systematic Review and Meta-Analysis of Different Protocols and Infertile Populations

This study investigates the effect of GnRHa pretreatment on pregnancy outcomes in artificial endometrial preparation for frozen-thawed embryo transfer (AC-FET) cycles. A systematic review of English language studies published before 1 September 2022, was conducted, excluding conference papers and preprints. Forty-one studies involving 43,021 participants were analyzed using meta-analysis, with a sensitivity analysis ensuring result robustness. The study found that GnRHa pretreatment generally improved the clinical pregnancy rate (CPR), implantation rate (IR), and live birth rate (LBR). However, discrepancies existed between randomized controlled trials (RCTs) and observational studies; RCTs showed no significant differences in outcomes for GnRHa-treated cycles. Depot GnRHa protocols outperformed daily regimens in LBR. Extended GnRHa pretreatment (two to five cycles) significantly improved CPR and IR compared to shorter treatment. Women with polycystic ovary syndrome (PCOS) saw substantial benefits from GnRHa pretreatment, including improved CPR and LBR and reduced miscarriage rates. In contrast, no significant benefits were observed in women with regular menstruation. More rigorous research is needed to solidify these findings.

Long-term health risk of offspring born from assisted reproductive technologies

Since the world's first in vitro fertilization baby was born in 1978, there have been more than 8 million children conceived through assisted reproductive technologies (ART) worldwide, and a significant proportion of them have reached puberty or young adulthood. Many studies have found that ART increases the risk of adverse perinatal outcomes, including preterm birth, low birth weight, small size for gestational age, perinatal mortality, and congenital anomalies. However, data regarding the long-term outcomes of ART offspring are limited. According to the developmental origins of health and disease theory, adverse environments during early life stages may induce adaptive changes and subsequently result in an increased risk of diseases in later life. Increasing evidence also suggests that ART offspring are predisposed to an increased risk of non-communicable diseases, such as malignancies, asthma, obesity, metabolic syndrome, diabetes, cardiovascular diseases, and neurodevelopmental and psychiatric disorders. In this review, we summarize the risks for long-term health in ART offspring, discuss the underlying mechanisms, including underlying parental infertility, epigenetic alterations, non-physiological hormone levels, and placental dysfunction, and propose potential strategies to optimize the management of ART and health care of parents and children to eliminate the associated risks. Further ongoing follow-up and research are warranted to determine the effects of ART on the long-term health of ART offspring in later life.

Intramuscular injection of human chorionic gonadotropin as luteal phase support in artificial cycle frozen-thawed embryo transfer does not improve clinical outcomes: a parallel, open-label randomized trial

Background

Human chorionic gonadotropin (hCG) as one of the first signals secreted by the embryo to the mother may have a direct effect on the endometrium at implantation. The current study was aim to compare the clinical outcomes after frozen-thawed embryo transfer (FET) treated with artificial cycles (AC) between women who were administered intramuscular injection of human chorionic gonadotropin (hCG) as luteal phase support and the routine group.

Methods

A randomized controlled trial of 245 women was conducted at the Assisted Reproduction Center, Northwest Women's and Children's Hospital, Xi'an, China from January 2019 to January 2020. Women <40 years of age undergoing their first FET treated with AC were included. Patients were randomly allocated into either: (1) the hCG treatment group, who received intramuscular injection of hCG since the third day of progesterone administration, at a dose of 2000 IU once every two days, for a total of four times, (2) the control group, receiving routine protocol without placebo on these four days. Clinical outcomes of the two groups were analyzed.

Results

The primary outcome ongoing pregnancy rate in the hCG treatment group versus the control group was 73/124 (58.87%) versus 75/121 (61.98%), respectively (odds ratio [OR], 95% confidence interval [CI]:0.88, 0.53-1.47, P = 0.619). Secondary clinical outcomes including biochemical pregnancy, clinical pregnancy, early pregnancy loss, multiple pregnancy, live birth and preterm birth were also comparable between the two groups through the univariate analysis and multivariable regression analysis (P > 0.05).

Conclusion

In women undergoing AC-FET, there was no significant difference in the clinical outcomes between the hCG treatment group and the control group. Clinicians should be cautious about adding IM-hCG as luteal phase support to improve the clinical outcome after AC-FET.

Clinical trial registration

http://www.chictr.org.cn/showprojen.aspx?proj=32511, identifier ChiCTR1800020342.

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.