The recovery of pre-ovulatory oocytes using a fixed schedule of ovulation induction and follicle aspiration.

Thirty-two volunteer women, scheduled for laparoscopy, were subjected to a fixed regimen of ovulation induction and ovarian follicle aspiration, following manipulation of the previous menstrual cycle with oral contraceptive pills or norethisterone. This allowed the time of oocyte recovery to be planned several weeks in advance. The recovery rate of mature oocytes (loosely dispersed cumulus) in the patients who had their cycles adjusted with norethisterone was comparable to that in a group of women treated in an embryo-transfer programme who were being individually monitored, although there was evidence from cleavage rates and concentration of sex steroids in follicular fluid that further follicular maturation could have occurred. It is suggested that a modification of this schedule could provide an acceptable recovery rate of pre-ovulatory oocytes for research purposes, and possibly by simplifying the monitoring technique could be applicable to a wider range of patients seeking embryo transfer.