Abstract
AIM: This study aims to investigate the influence of elevated preovulatory progesterone (P4) on the outcome of in vitro fertilization (IVF). MATERIALS AND METHODS: This was a prospective cohort study conducted at the Clinic for Women's Diseases and Childbirth in Petrova, Zagreb, Croatia, in the period 2015-2017, which included a total number of 400 patients (300 in the control group and 100 in the group with elevated preovulatory P4). The study group was furthermore divided into normal responders (85 patients) and high responders (15 patients). The IVF outcome among patients with normal preovulatory P4 as compared to the patients with elevated preovulatory P4, the IVF outcome among normal and high responders, the influence of the embryo transfer type - blastocyst embryo transfer (BET) or frozen/thawed embryo transfer (FET) - among patients with elevated preovulatory P4 on the outcome of IVF procedures has been investigated in this study. RESULTS: Positive IVF outcome has been recorded in about one third of all the performed procedures in the control and the study group (P=0.762 for the conception rate and P=0.245 for the clinical pregnancy rate), with slightly better outcome with elevated preovulatory P4. A better outcome with FET has been observed among normal responders (P=0.019), and a slightly better outcome with BET has been noted among high responders (P=0.622). CONCLUSION: Elevated preovulatory P4 has a slightly protective effect on IVF outcome, while the P4 on the fifth day >425.7 nmol/L could be a potential marker for the success of the IVF procedures among all the patients, and with P4 on the fifth day >384.6 nmol/L among patients with elevated preovulatory P4.