Pituitary-ovarian function in mothers who have had two sets of dizygotic twins.

Serum gonadotropin and estradiol levels were measured in 14 women with regular menses during the early and midfollicular phases. Early follicular follicle-stimulating hormone and, to a lesser extent, luteinizing hormone levels were significantly higher in a group of eight women who had had at least one set of dizygotic twins (six of whom had had two sets) than in a control group of six women with no dizygotic twins. Estradiol levels also tended to be higher in mothers of twins, particularly in the midfollicular phase. The two groups of women did not differ in age, height, weight, or parity.