The role of progesterone elevation on in vitro fertilization (IVF) outcome has remained a debatable issue for several years. The aim of this systematic review and meta-analysis was to evaluate whether progesterone elevation on the day of human chorionic gonadotrophin (hCG) administration is associated with the probability of pregnancy. Eligible studies were considered those in which patients did not participate more than once. A literature search in MEDLINE, EMBASE and CENTRAL identified 12 eligible studies, 10 of which were retrospective. The majority (n = 10) of these studies did not detect a statistically significant association between progesterone elevation and the probability of pregnancy. Meta-analysis was performed only for the studies (n = 5) that provided data on clinical pregnancy per patient reaching hCG administration for final oocyte maturation. No statistically significant association between progesterone elevation and the probability of clinical pregnancy was detected (Odds ratio: 0.75, 95% confidence interval 0.53-1.06; P = 0.10). This finding persisted in the sensitivity analyses performed, which excluded the studies that did not report clearly that measurement of progesterone did not affect patients' management and those that did not report definition of clinical pregnancy. In addition, subgroup analyses were conducted on the basis of type of gonadotrophin-releasing hormone GnRH analogue used and on the value of serum threshold used to classify patients in those with or without progesterone elevation. These analyses, however, did not materially change the results obtained. In conclusion, the best available evidence does not support an association between progesterone elevation on the day of hCG administration and the probability of clinical pregnancy in women undergoing ovarian stimulation with GnRH analogues and gonadotrophins for IVF.