Human chorionic gonadotropin-to-oocyte collection interval in a superovulation IVF program. A prospective study

Purpose: The aim of this study was to investigate whether the hCG-oocyte co llection interval has any influence on the oocyte recovery rate, fertilizat ion rate, and outcome of IVF-ET cycles. Methods: Five hundred thirty-three consecutive patients undergoing their fi rst IVF-ET treatment cycle at King's Assisted Conception Unit between 1993 and 1995 were included in this study. Results: There was no significant difference in the oocyte recovery rates f ertilization rates, or outcome of IVF-ET treatment among the hCG-oocyte col lection intervals examined (33-41 hr). None of the 533 women studied had ov ulated before oocyte collection. Conclusions: The results do not suggest a trend toward increased ovulation more than 36 hr after h CG administration.