Does anovulation induced by oral contraceptives favor pregnancy during the following two menstrual cycles?

OBJECTIVE: To compare IVF and pregnancy outcomes before and after anovulation induced by oral contraceptives.

DESIGN: Observational clinical study.

SETTING: Infertility clinic.

PATIENT(S): Forty women with two intact ovaries (32 of 40 couples with male factor infertility and 8 with unknown causes of infertility) underwent 190 IVF treatment cycles (55 natural cycles and 135 clomiphene citrate-stimulated cycles).

INTERVENTION(S): If the women failed to conceive after 2-4 IVF treatment cycles, oral contraceptives were used to induce anovulation for 1 month before IVF was performed in two consecutive cycles.

MAIN OUTCOME MEASURE(S): Rates of oocyte retrieval, fertilization, cleavage, preembryo formation, pregnancy, and implantation were compared before and after a period of anovulation.

RESULT(S): The pregnancy rate per cycle of the first and second cycle combined (23%) and that of the second cycle alone (30%) after a period of anovulation were significantly higher than that observed before a period of anovulation (9%).

CONCLUSION(S): Anovulation induced by oral contraceptives, showing bilateral ovarian quiescence, enhances pregnancy rates in the following two menstrual cycles of IVF treatment.