The luteal phase during gonadotropin therapy: effects of two human chorionic gonadotropin regimens

Luteal phase abnormalities are known to complicate ovulation induction with gonadotropins. This study was performed to test the effect of a modified human chorionic gonadotropin (hCG) regimen on the luteal phase during gonadotropin treatment.

Fifteen women from a private practice setting volunteered to be studied during each of two nonconception, gonadotropin-stimulated cycles. After ovarian stimulation with human menopausal gonadotropins (hMG), hCG was administered either as a single dose of 10,000 IU (single dose) or in two divided doses of 5,000 IU given 1 week apart (split dose).

Early, midluteal, and late luteal estradiol (E2) and progesterone (P) levels and luteal phase lengths were measured, and their median values and intraquartile ranges (IQR) compared using nonparametric analysis.

Early and midluteal E2 and P levels were similar regardless of which hCG regimen was administered. The median late luteal E2 level was 1,146.0 pg/mL (the IQR ranged from 633 to 1,650, IQR = 1,017) with the split-dose regimen and 240.0 pg/mL (the IQR ranged from 150 to 460, IQR = 310) with the single-dose regimen. The median late luteal P level was 108.0 ng/mL (the IQR ranged from 58.5 to 129, IQR = 70.5) with the split-dose regimen and 4.2 ng/mL (the IQR ranged from 1.9 to 11.7, IQR = 9.8) with the single-dose regimen. Median luteal phase lengths were 16 days (the IQR ranged from 15 to 17, IQR = 2) for the split-dose regimen and 11 days (the IQR ranged from 10 to 12, IQR = 2) for the single-dose regimen.

In hMG-stimulated cycles, a second dose of hCG given during the midluteal phase significantly increases late luteal E2 and P levels and consistently lengthens the luteal phase.