Premature luteinization as detected by elevated serum progesterone is associated with a higher pregnancy rate in donor oocyte in-vitro fertilization.

Premature luteinization has been reported to be associated with decreased pregnancy rates in patients undergoing in-vitro fertilization. However, the detrimental effect created by a pre-aspiration rise in progesterone is difficult to assess since ovarian stimulation affects both oocyte quality and endometrial receptivity. Therefore, the relationship between premature luteinization and pregnancy rates remains uncertain. To achieve improved control for confounding variables, we studied premature luteinization in ovum donors of proven fertility. A total of 114 consecutive ovum donation cycles using pituitary suppression with a gonadotrophin-releasing hormone agonist followed by gonadotrophin stimulation were examined. Serum progesterone concentration on the day of administration of human chorionic gonadotrophin (HCG) was > 1.2 ng/ml in 29% of patients. Patients were divided into two groups based on this value. There was a significant increase in clinical pregnancy rates per embryo transfer in the group with higher progesterone concentrations (53 versus 25%, P = 0.012), as well as significantly more oocytes obtained at aspiration (19.6 +/- 10.4 versus 13.3 +/- 5.4, P < 0.001), and significantly higher peak serum oestradiol values (3903 +/- 1787 versus 2453 +/- 1232 pg/ml, P < 0.001). There were no significant differences between groups due to age, degree of stimulation or the number of embryos transferred. We conclude that premature luteinization as based on elevated serum progesterone concentration is a common occurrence in oocyte donors, reflects healthy follicular development, and is associated with increased pregnancy rates.