Low dose recombinant FSH treatment may reduce multiple gestations caused by controlled ovarian hyperstimulation and intrauterine insemination

Objective  To evaluate the rate of multiple pregnancies in intrauterine insemination cycles stimulated with a minimal dose of recombinant follicle stimulating hormone (rec-FSH). Design  Retrospective study. Setting  University Medical Center. Population  A total of 1256 patients underwent 3219 consequent intrauterine insemination cycles with minimal ovarian stimulation. Methods  Patients received 50 or 75 IU of rec-FSH from day four to day seven. The dose was adjusted according to oestradiol (E2) levels in order to achieve a maximum of two follicles on the day of hCG administration. Main outcome measures  Peak E2 levels, the number of follicles >15 mm and pregnancy rates were calculated. The predictive value of E2 levels for multiple gestations was also estimated. Results  Of 3219 cycles, 334 resulted in pregnancies (10%). Of these, 238 (91%) were singletons, 28 (8%) twins and 1 (0.3%) was a triplet. The cumulative overall pregnancy rate was 43%. Patients over 40 years old had a significantly lower pregnancy rate per cycle and overall live birth rate (P < 0.05). Most pregnancies (83%) occurred during the first three cycles. Pregnancy rates per cycle varied from 8% for tubal factor to 14% for anovulation infertility. Conclusions  Minimal FSH stimulation in intrauterine insemination cycles may reduce the rates of twins and high order multiple pregnancies without affecting overall pregnancy rates.