No improvement in pregnancy and perinatal outcomes with combined luteal support in modified natural cycle frozen embryo transfer

Abstract

Objective: We investigated whether the addition of a luteal phase support drug benefits pregnancy and perinatal outcomes in modified natural-cycle frozen-thawed embryo transfer (mNC-FET) for women up to the age of 35 years. Methods: We analyzed the clinical data of 3658 mNC-FET cycles of women up to the age of 35 years from the Reproductive Center of the Third Affiliated Hospital of Zhengzhou University from January 2018 to December 2020 in a retrospective cohort study. The cycles were divided into three groups based on the luteal phase support protocol used. The patients in group A received a combination of progesterone soft capsules and dydrogesterone (882 cycles), those in group B received dydrogesterone only (627 cycles), and those in group C received a combination of progesterone vaginal sustained-release gel and dydrogesterone (2149 cycles). Pregnancy and perinatal outcomes were compared among the three groups. Results: Logistic regression analysis indicated that the three luteal phase support regimens were not associated with the live birth rate [OR(95% CI)B vs A=1.080, p=0.960; OR(95% CI)B vs C=0.252, p=0.291]. There were no significant differences in the newborn weight, premature delivery rate, pregnancy complications rate, and incidence of birth defects among the three groups. Conclusions: In the mNC-FET cycle, patients under the age of 35 who chose dydrogesterone alone as a luteal phase support drug exhibited no difference in the live birth rate and perinatal outcome from patients who combined dydrogesterone with progesterone soft capsules or with progesterone vaginal sustained-release gel. However, the outcome still requires confirmation by large-sample prospective studies.