FERTILITY, IVF AND REPRODUCTIVE GENETICS: Edited by Emre Seli and Juan Antonio García VelascoSignificance of premature progesterone rise in IVFFatemi, Human M.a; Van Vaerenbergh, IngebAuthor Information aNova IVI Fertility, Abu Dhabi, UAE bReproductive Immunology and Implantation, Vrije Universiteit Brussel, Brussel, Belgium Correspondence to Prof. Dr Human M. Fatemi, Nova IVI Fertility Clinic, LLC, P.O. Box 60202, Royal Marina Office, Abu Dhabi, UAE. Tel: +97122222844; fax: +97122222874; e-mail: email@example.com Current Opinion in Obstetrics and Gynecology: June 2015 - Volume 27 - Issue 3 - p 242-248 doi: 10.1097/GCO.0000000000000172 Buy Metrics Abstract Purpose of review The current review will focus on the cause of premature progesterone and its impact on endometrial receptivity and endometrial gene expression. Recent findings Premature progesterone rise in stimulated IVF cycles seems to have a negative impact on the pregnancy rate. The current knowledge on the cause of a premature progesterone rise is still limited; however, it seems that overstimulating the ovaries during the end of the follicular phase will lead to a premature progesterone rise. The negative impact on the outcome is mainly due to reduced endometrial receptivity as can be seen in the altered endometrial gene expression. Summary Future studies should focus on how ovarian stimulation can be tailored according to individual requirements of the patients, aiming on preventing a possible progesterone rise during follicular phase of stimulated IVF cycles. Copyright © 2015 YEAR Wolters Kluwer Health, Inc. All rights reserved.