Small increases in circulating luteinizing hormone (LH) concentrations shortly before human chorionic gonadotropin (hCG) are associated with reduced in vitro fertilization (IVF) pregnancy rate.

The effects of slight elevations in serum LH just before hCG administration on IVF cycle outcome were studied in 219 women undergoing retrieval. One hundred seven patients were stimulated using human menopausal gonadotropin (hMG), and 112 received clomiphene citrate and hMG. Serum LH, estradiol (E2), and progesterone concentrations were measured before and during controlled ovarian stimulation. Retrospectively the women were subdivided into three groups based on serum LH before hCG: Group I, less than 50% LH rise from baseline (BL) value (mean of day 2 and day 7); Group II, LH rise greater than or equal to 50% but less than 2 x BL; and, Group III, LH rise greater than or equal to 2 x BL. The fertilization and cleavage rates were similar in all groups. However, a greater than or equal to 50% rise in serum LH before hCG was associated with a significantly reduced IVF pregnancy rate.