Endocrine profiles in early pregnancies with delayed implantation

Delayed implantation in cycles with ovarian stimulation and ovulation induction was observed in eight patients. Endocrinological evidence for ovulation during pregnancy is presented in three cases; in one of them the implantation was evidently rescued by a new active corpus luteum. All pregnancies had the following factors in common: (1) A delay in the detection of the first positive serum human chorionic gonadotrophin (HCG) by 4-5 days. (2) The corpus luteum was not rescued initially and menstruation started at low serum concentrations of 17 beta-oestradiol and progesterone between 12 to 18 days (13.8 +/- 1.9 days) after induction of ovulation. (3) Because of the negative HCG, menstrual bloodloss and low steroid hormone concentrations, a new ovarian stimulation was started and continued for some days until pregnancy was detected. On the basis of the endocrine findings, three different forms of delayed implantation could be distinguished. Two of the eight pregnancies had a normal progression until full-term delivery, two developed into echographically-confirmed clinical pregnancies, but aborted at 9 and 11 weeks after the first menstrual period had started. The remaining four ended with a preclinical abortion between 7 and 8 weeks.