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 increasedrisk of ovarian hyperstimulation syndrome (OHSS). The aim ofthis study was to assess the beneficial effect of the mid-lutealaddition of human choriomc gonadotrophin (HCG) in IVF, usinga down-regulation protocol and luteal support with progesterone,in a prospective randomized study. The study included 170 IVFcycles down-regulated with long-acting GnRHa which were supportedwith 50 mg/day progesterone i.m. during the luteal phase. Patientswere evaluated in the mid-luteal period. Those without clinicalsigns of OHSS, oestradiol concentrations <1000 pg/ml andprogesterone concentrations <50 mg/ml were randomly allocatedto either the addition of 2500 IU HCG (HCG+ group) or no HCG(HCG– group). End luteal phase progesterone concentrationsamong non-pregnant patients were used to assess the contributionof exogenous progesterone and to categorize pregnancies accordingto their corpus luteum function. Similar low OHSS (2.7 and 1.8%)and pregnancy (30 and 29%) rates were observed in the HCG+ andHCG– groups respectively. Of the 26 pregnancies in theHCG+ cases, there was only one case with reduced corpus luteumfunction, compared with 12 of the 25 pregnancies among HCG–patients. Cases with reduced corpus luteum function requiredcontinuous progesterone support and presented lower HCG concentrationsand a higher rate of adverse pregnancy outcome. We concludethat mid-luteal HCG addition does not affect pregnancy rate,but in fact helps to preserve corpus luteum function and avoidsthe need for further supplementation during early pregnancy.