(982) Maternal and neonatal outcomes associated with route of progesterone administration in frozen embryo transfers

Objective: To determine if the route of progesterone administration in medicated single euploid frozen embryo transfers (FET) affects the incidence of adverse maternal and neonatal outcomes.

Study Design: This was a retrospective cohort of all patients who underwent a single euploid FET at a single IVF center resulting in delivery at one of seven hospitals within a large academic health system in New York from January 2020-July 2023. For patients with more than one pregnancy during the study period, only the first was included for analysis. Patients with multiple gestation pregnancies and those who delivered at less than 23 weeks of gestation were excluded. Patients were divided into three groups based on route of progesterone administration: intramuscular progesterone only (IM), vaginal progesterone only (Vag), and combination of IM and Vag progesterone (IM+Vag). Demographic information, clinical characteristics and pregnancy outcomes were obtained. Maternal and neonatal outcomes were compared between the three groups using ANOVA with p< .05 considered significant.

Results:

A total of 335 patients were included in the study (Table): 234 IM, 74 Vag, 27 IM+Vag. The patients in all groups were mostly non-Hispanic white, >35 years old, overweight, married, and English speaking. There were no differences in maternal or neonatal outcomes between the three groups.

Conclusion:

The route of progesterone administration in pregnancies achieved via FET is not associated with adverse maternal or neonatal outcomes. Vaginal progesterone may be considered to minimize discomfort for patients undergoing fertility treatment. Larger prospective studies are still warranted.