Daily serum choriogonadotropin concentrations in early human gestation

Fifteen regularly menstruating, healthy women were studied from day 10 of the menstrual cycle to either confirmation of pregnancy or spontaneous menses. Daily blood samples were obtained and serum luteinizing hormone (LH), human chorionic gonadotropin hormone (hCG), 17 beta-estradiol and progesterone were determined by means of specific radioimmunoassay (RIA). Two of the women experienced spontaneous conception with a rise in hCG on 12 and 13 days after LH peak.