Addition of intramuscular to vaginal progesterone for luteal phase support in fresh embryo transfer cycles: A cross-sectional study

Background: Luteal phase deficiency is common in assisted reproductive technology and is characterized by inadequate progesterone production. Various studies have shown that administration of progesterone in fresh embryo transfer cycles increases the rate of clinical pregnancy and live birth rate. Progesterone administration has variable types: oral, vaginal, oil-based intramuscular, and subcutaneous. Objective: This study aims to compare the effect of adding intramuscular progesterone to the vaginal progesterone for luteal phase support in the fresh embryo transfer cycle. Materials and Methods: This study reviewed the information related to 355 women who had a fresh embryo transfer between March 2020 and February 2021 at the Yazd Reproductive Sciences Institute, Yazd, Iran. The participants population were divided into 2 groups based on the type of luteal phase support regime: group I (n = 173) received 400 mg vaginal progesterone alone twice a day from the day of ovum pick up; and group II (n = 182) received 50 mg IM of progesterone in addition to vaginal progesterone 400 mg twice a day from the day of ovum pick up. Chemical and clinical pregnancy rates were compared between groups. Results: The basic characteristics of groups were statistically similar. The rates of chemical and clinical pregnancy were higher in the vaginal plus IM progesterone group than in the vaginal progesterone group. Moreover, chemical pregnancy showed a significant difference between the groups (p = 0.011). Conclusion: Our findings demonstrated that the addition of IM progesterone to the vaginal progesterone improves the chemical pregnancy rate in fresh embryo transfer.