IS PROGESTERONE SUPPLEMENTATION REQUIRED FOR LUTEAL PHASE SUPPORT DURING MODIFIED NATURAL CYCLE FROZEN EMBRYO TRANSFER?

Abstract

Objective

Is there a difference in pregnancy outcomes among women undergoing modified natural cycle frozen embryo transfer (mNC-FET) with or without progesterone as luteal phase support (LPS)?

Materials and Methods

A retrospective analysis was conducted on 2216 modified natural cycle frozen embryo transfer (mNC-FET) cycles performed at Memorial Sisli Hospital between 2011 and 2023. The study included patients under 38 years of age who underwent top-quality (TQ) or good-quality (GQ) single embryo transfer in mNC-FET cycles. Excluded from the study were medium-quality (MQ) or poor-quality (PQ) embryo transfer cycles, double embryo transfer cycles, and embryo transfer cycles with preimplantation genetic testing for aneuploidy (PGD/A). During the mNC-FET cycles, patients were monitored using transvaginal ultrasonography starting from the second day of the menstrual cycle to determine the day of ovulation. Based on follicle size and hormone levels, ovulation was induced with a single subcutaneous dose of recombinant human chorionic gonadotropin (r-hCG, Ovitrelle 250 µg). The cycles were divided into three separate groups for analysis: Group A (n=493) did not receive any luteal phase support; Group B (n=1327) received 200 mg of vaginal micronized progesterone twice daily; and Group C (n=396) received 200 mg of vaginal micronized progesterone twice daily along with 25 mg of subcutaneous progestin daily. Groups were compared in terms of cycle characteristics and pregnancy outcomes.

Results

Demographic and fresh cycle characteristics of the groups were similar. There was no statistically significant difference between the groups regarding pregnancy outcomes. Live birth rates were 58.4% in Group A, 60.8% in Group B and 60.1% in Group C (p=0.650). Clinical pregnancy rates were 65.9%, 69.1% and 68.2%, respectively (p=0.432). Biochemical abortion rates were 4.5%, 6.6% and 5.3%, respectively (p=0.186) and clinical abortion rates were 6.3%, 6.7% and 5.3%, respectively (p=0.828).

Conclusion

The study showed that women under 38 years of age undergoing mNC FET had similar pregnancy outcomes with or without the use of progesterone for luteal phase support. Consequently, the administration of progesterone for luteal phase support seems unnecessary. In these cases, hCG given for triggering and the presence of corpus luteum are sufficient for luteal phase support. Randomised controlled trials are needed to support these findings.