EMBRYO IMPLANTATION DURING MENSTRUATION IN THE ABSENCE OF ADEQUATE ESTRADIOL AND PROGESTERONE SUPPORT, WITH SUBSEQUENT NORMAL RESPONSE TO OVULATION INDUCTION AND SUPERFETATION

Objective: To report an unusual case of embryo implantation and superf etation.Design: Retrospective case analysis. Setting: Oak Brook Fertil ity Center. Patient(s): A 41-year-old woman underwent two consecutive ovarian stimulation cycles interrupted by a normal menstrual period. O vulation and implantation occurred during both cycles. The first embry o conceived developed normally until term; the second failed to develo p. Intervention(s): None. Main Outcome Measure(s): Retrospective analy sis of stored blood samples for serum E-2, P, and beta-hCG levels. Res ult(s): Rising beta-hCG levels during menstruation indicated normal em bryonic implantation in the absence of adequate E-2 and P support, Dur ing subsequent ovarian stimulation, there was a normal follicular and E-2 response and normal ovulation in spite of the ongoing pregnancy. T he second embryo, conceived during the second cycle of stimulation, im planted but failed to develop. Conclusion(s): This unusual case indica tes that E-2, P, and endometrial thickness requirements for successful implantation may not always be as critical as postulated previously. The absence of a decidual response might have facilitated superfetatio n. (C) 1997 by American Society for Reproductive Medicine.