DAILY MEASUREMENTS AND IN-VITRO EFFECTS OF HUMAN CHORIONIC-GONADOTROPIN IN THE EARLY LUTEAL-PHASE

The purpose of the present study was to analyse daily measurements of human chorionic gonadotrophin (HCG) in in-vitro fertilization (IVF) cy cles and to reproduce the effects of HCG in vitro using human granulos a - luteinized cells from the same patients. The study population cons isted of nine women undergoing IVF because of tubal infertility in who m blood was drawn every 24 h from the day of the ovulatory dose of HCG (10 000 IU) until 6 days after ovum pick-up. Granulosa-luteal cells f rom the follicular aspirates were collected and cultured in vitro up t o 6 days in the presence of increasing concentrations (0, 0.01, 0.1, 1 .0 and 100.0 IU/ml) of HCG. Serum progesterone and HCG in vivo as well as progesterone accumulation in vitro on days 2, 4 and 6, were the ma in outcome measures. Maximum HCG concentrations (0.25 IU/ml) were reac hed the day before ovum pick-up, and continuously decreased until day 6 after ovum retrieval. HCG did not stimulate progesterone production in vitro at any dose tested until day 6 after ovum pick-up. Then, 0.01 IU/ml resulted significantly (P < 0.05) stimulatory compared to contr ols, while 1.0 IU/nil was inhibitory (P < 0.05). It is concluded that HCG supplementation in an IVF cycle is unnecessary until day 6 after o vum pick-up. On day 6, progesterone production is stimulated with very low concentrations of HCG.