The use of pure FSH alone or in combination for ovulation stimulation in in vitro fertilization

The experience of the Norfolk Program, from the beginning of 1981 until mid 1984, is reviewed. Two groups of patients are compared. The initial experience goes from the very beginning until early 1984 in which knowledge has accumulated; the patients treated afterwards up to mid 1984 where the previous experience was used to monitor them in a more accurate way is reviewed as a separate category. Different protocols, in each group, are compared: concomitant combination of hFSH/hMG (protocol # 1), sequential combination of the two gonadotropins (protocol # 2), and pure FSH administration (protocol # 3). Several parameters were used in the evaluation of the results: 1) day of laparoscopy, 2) volume of the follicles obtained, 3) number of preovulatory oocytes obtained, 4) number of immature oocytes obtained, 5) number of atretic oocytes induced, 6) number of oocytes with abnormal zona pellucida, 7) fertilization rate of preovulatory and immature oocytes, 8) abnormal fertilization rate of preovulatory and immature oocytes, 9) cleavage rate of the normally fertilized preovulatory immature oocytes, 10) transfer rate, single and multiple, 11) follicular and luteal phases as evaluated by estradiol levels in the preovulatory phase and by E₂ and progesterone in the post ovulatory phase, 12) pregnancy rate. Pure FSH seems to prolong somewhat the follicular phase. Preovulatory oocytes derived from small follicles may originate pregnancies that may end in abortion. The concomitant combination rendered a larger number of preovulatory oocytes. The number of immature oocytes tend to be higher in the pure FSH stimulated group, but this seems to depend on the way FSH is used. The normal fertilization rate for preovulatory oocytes tends to be similar as the criteria used in the stimulation protocol improved. The abnormal fertilization rate for both types of oocytes decreased in the latest series. The number of embryos transferred was higher in the concomitant combination stimulation. Shortening the hMG/hCG interval in the pure FSH category seems to induce a deficient follicular phase except in cases with rapid high response. When using the hFSH/hMG combination the values of estradiol in the follicular phase tend to be much higher than when the original pure hMG protocol is used. This does not seem to be true when pure FSH stimulation is used. The number of multiple transfers increased substantially in both types of stimulation as experience increased. Nevertheless, in terms of pregnancy rate the addition of FSH does not seem to significantly improve the outcome of in vitro fertilization although further experience is needed in trying to improve the criteria for monitoring these patients.