Endocrinology: Daily measurements and in-vitro effects of human chorionic gonadotrophin 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) cycles and to reproduce the effects of HCG in vitro using human granulosa-luteinized cells from the same patients. The study population consisted of nine women undergoing IVF because of tubal infertility in whom 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 from the follicular aspirates were collected and cultured in vitro up to 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 main outcome measures. Maximum HCG concentrations (0.25 IU/ml) were reached 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 controls, while 1.0 IU/ml was inhibitory (P < 0.05). It is concluded that HCG supplementation in an IVF cycle is unnecessary until day 6 after ovum pick-up. On day 6, progesterone production is stimulated with very low concentrations of HCG.