BACKGROUND: Gonadotrophin-releasing hormone (GnRH) antagonists have been proven safe and effective, with no adverse effects on offspring in animal studies. Careful study of pregnancy outcome in humans is mandatory. METHODS AND RESULTS: This preliminary report includes follow-up data of patients treated with the GnRH antagonist, ganirelix, during ovarian stimulation for IVF or ICSI. In total, 333 patients were randomized in a multicentre, double-blind, dose-finding study of ganirelix, at six different doses ranging from 0.0625 to 2 mg. In total, 68 vital intrauterine pregnancies were established that resulted in the birth of 46 singletons, 12 twins and one triplet. Follow-up of the 67 pregnant patients (one subject was lost to follow-up) revealed six miscarriages (9%). Of the 61 subjects with an ongoing pregnancy, two with a singleton pregnancy did not give birth to a live-born infant (one spontaneous abortion in week 19, and one intrauterine death in week 27). The mean gestational age was 39.4 weeks for singleton pregnancies, and 36.6 weeks for multiple pregnancies. In total, 73 infants (33 boys, 40 girls) were born. A birth weight < 2500 g was reported for 8.7% and 54.2% of the infants resulting from singleton and twins delivery respectively. One major congenital malformation was diagnosed; a boy with Beckwith-Wiedemann syndrome (exomphalos and macroglossia). Seven minor malformations were reported among five infants. CONCLUSIONS: In this first follow-up study, the incidence of adverse obstetrical and neonatal outcome was comparable with reported incidences for IVF-embryo transfer pregnancies.
