CUMULATIVE PREGNANCY RATE FROM ONE GAMETE INTRAFALLOPIAN TRANSFER (GIFT) CYCLE WITH CRYOPRESERVATION OF EMBRYOS - A PRACTICAL MATHEMATICAL CALCULATION

We evaluated the cumulative pregnancy rate from one gamete intra-Fallopian transfer (GIFT) cycle plus subsequent cycles in which embryos cryopreserved at the time of the original GIFT cycle were transferred. All patients who had their first GIFT cycle in our centre between January, 1989 and March, 1991 were included. Ovarian stimulation was accomplished with leuprolide acetate (luteal phase protocol) and a combination of follicle stimulating hormone and human menopausal gonadotrophin. GIFT was performed with three to five oocytes. Excess oocytes were inseminated and good quality embryos were cryopreserved at the 2- to 4-cell stage with 1-2 propanediol. When the GIFT cycle did not result in a pregnancy, uterine transfer of cryopreserved embryos was carried out in subsequent unstimulated cycles. A total of 97 patients had GIFT and 46 pregnancies were achieved (47.4%). A total of 51 patients (52.5%) had embryos frozen; of these, 21 were from the non-pregnant group (41.1%) and 30 from the pregnant group (65.2%) (P < 0.05). Up to now, 22 of them have undergone a frozen-thawed embryo transfer cycle, and two of them achieved a pregnancy. Based on these data, patients having a GIFT could theoretically expect a cumulative pregnancy rate of 52.2%.