Comparison of maternal serum estradiol and progesterone levels in pregnancies after induced and spontaneous ovulation.

Maternal serum estradiol and progesterone levels during the early 6th to 15th weeks of gestation, were measured by radioimmunoassay in 140 pregnancies following induction of ovulation with gonadotropins or clomiphene citrate. The levels were compared with those observed in 79 spontaneous pregnancies. Significantly higher levels were observed in gonadotropin and clomiphene citrate induced pregnancies (both P values less than 0.001) between the 6th to 9th week of gestation as compared to spontaneous pregnancies. Steroid levels were similar in the two groups from the 9th week onwards. No statistically significant differences in steroid hormone values were observed in aborted and successful pregnancies within each group studied. We conclude that ovulation induction is associated with higher estradiol and progesterone levels until placental steroidogenesis starts.