IATROGENIC MULTIPLE PREGNANCIES IN EAST FLANDERS, BELGIUM

Objective: To evaluate the specific contribution of artificial inducti on of ovulation to the increasing number of multiple gestations in Eas t Flanders and the effects of this treatment on the frequencies of mon ozygotic and dizygotic twinning. Design: Since 1976 the East Flanders Prospective Twin Study has collected data on artificial induction of o vulation for all the multiple births listed in its registry. Setting: East Flanders Prospective Twin Survey. Patients: Between 1976 and 1992 , 458 twin and 78 triplet pregnancies resulting from artificial induct ion of ovulation were analyzed. Main Outcome Measures: Zygosity and fr equency of iatrogenic multiple births. Results: Since 1985 there is an explosive increase in twin and triplet births in East Flanders. This increase has been caused mainly by the sole use of fertility-enhancing drugs and in the last few years by resorting to other technologies of assisted reproduction, such as IVF-ET, GIFT, or zygote intrafallopian transfer. Conclusion: In view of the elevated risk inherent to multip le pregnancies in terms of perinatal mortality and morbidity, the over enthusiastic or improper use of fertility drugs should be curtailed.