Received June 24, 2014
Accepted October 01, 2014

Objective: To determine whether administration of progesterone on the day of oocyte retrieval may reverse accumulation of fluid in the endometrial cavity. Methods: A total of 50 patients who underwent assisted reproductive technology (ART) cycles with endometrial cavity fluid (ECF) observed by ultrasound at the time of oocyte retrieval were included. Upon the identification of ECF, vaginal administration of natural progesterone was started. Two days later, the endometrial cavity was re-evaluated, and embryo transfer was performed in the absence of ECF. Results: ECF was absent two days after administration of vaginal progesterone in 47 of the 50 patients (94%). ECF persisted in 3 of the 50 patients (6%). The clinical pregnancy rate per transfer was 34.0%, and the implantation rate was 21.6%. Conclusion: Our data suggest that, in the presence of ECF, administration of intravaginal progesterone in ART cycles must be initiated on the day of follicle aspiration to reverse ECF and to avoid the deleterious effects of fluid on the blastocyst-endometrial interaction.