The benefits of mid-luteal addition of human chorionic gonadotrophin in in-vitro fertilization using a down-regulation protocol and luteal support with progesterone.

Luteal support is essential in in-vitro fertilization (IVF) when long-acting gonadotrophin-releasing hormone agonist (GnRHa) is used. Because progesterone lacks luteotrophic stimulation, it seems to be the drug of choice in cases with an increased risk of ovarian hyperstimulation syndrome (OHSS). The aim of this study was to assess the beneficial effect of the mid-luteal addition of human chorionic gonadotrophin (HCG) in IVF, using a down-regulation protocol and luteal support with progesterone, in a prospective randomized study. The study included 170 IVF cycles down-regulated with long-acting GnRHa which were supported with 50 mg/day progesterone i.m. during the luteal phase. Patients were evaluated in the mid-luteal period. Those without clinical signs of OHSS, oestradiol concentrations <1000 pg.ml and progesterone concentrations <50 ng/ml were randomly allocated to either the addition of 2500 IU HCG (HCG+ group) or no HCG (HCG- group). End luteal phase progesterone concentrations among non-pregnant patients were used to assess the contribution of exogenous progesterone and to categorize pregnancies according to their corpus luteum function. Similar low OHSS (2.7 and 1.8%) and pregnancy (30 and 29%) rates were observed in the HCG+ and HCG-groups respectively. Of the 26 pregnancies in the HCG+ cases, there was only one case with reduced corpus luteum function, compared with 12 or the 25 pregnancies among HCG-patients. Cases with reduced corpus luteum function required continuous progesterone support and presented lower betaHCG concentrations and a higher rate of adverse pregnancy outcome. We conclude that mid-luteal HCG addition does not affect pregnancy rate, but in fact helps to preserve corpus luteum function and avoids the need for further supplementation during early pregnancy.