Modified Natural Cycle for In Vitro Fertilization and Embryo Transfer in Normal Ovarian Responders

Controlled ovarian hyperstimulation (COH) using a gonadotrophin-releasing hormone (GnRH) analogue plus gonadotrophins is used widely in in vitro fertilization (IVF), but there can be significant complications. Sixty women with a normal ovarian response participated in a comparison of COH (triptorelin [GnRH agonist] 0.1 mg/day SC from day 21 of the menstrual cycle [before the IVF cycle] and recombinant follicle-stimulating hormone (FSH) 150 300 IU/day from day 2 of the IVF cycle, when triptorelin was reduced to 0.05 mg/day) with a modified natural cycle (MNC) treatment (human menopausal gonadotrophin [HMG] 150 IU/day IM if serum oestradiol was <= 50 pg/ml on day 2 or 3 of the menstrual cycle). The groups did not differ significantly in implantation rate (21.1% and 22.6%, respectively) and clinical pregnancy rate (30.0% and 30.0%, respectively). When comparing successful pregnancies, MNC patients had significantly lower values than COH patients for total amount of gonadotrophin (HMG and recombinant FSH) used, number of oocytes retrieved and medication cost. It is concluded that MNC seems to be a feasible treatment option, with low medication cost, relatively low risk of complications and, possibly, greater patient acceptability.