title: [Obstetric outcome among naturally and IVF conceived twins.].
abstract: Pregnancy and delivery are generally perceived to be more hazardous among twins compared to singletons. Assisted conception techniques have increased the number of twins, but the effect on obstetric management and outcome is not well known. During 1990-1993 there were 254 twin pregnancies of 5? 16 weeks gestation in Iceland, of which 52 (20.5%) were after IVF; - a twin rate of 1:73 deliveries. The natural rate was 1:90. IVF women were on average 3 years older but of equal height and smoking habits as the natural mothers. Mean gestational age was 36 +/-3.68 (SD) weeks for both IVF and natural twins. In 61.9% labour commenced spontaneously after natural conception, compared to 51.9% after IVF (N.S.) and 64.4% of natural and 58.8% of IVF twins were delivered normally (N.S.). Caesarean section rates were almost equal, but there were twice as many forceps and ventouse deliveries of IVF babies (p<0.02). There appeared to be a minor tendency for more frequent elective Cesarean section in IVF pregnancies, but emergency section was more prevalent among those who conceived naturally. IVF twins were on average 64g lighter (mean birthweight 2552g) than natural twins (mean birthweight 2616g), which was unaffected by smoking habits and gestional length. The sex ratio was higher among IVF twins. IVF twins were more often admitted to neonatal intensive care, but remained there a shorter time. This suggests a lower threshold for admission of twins conceived following IVF treatment. Perinatal mortality was not different among natural compared to IVF twins; 20/1000 by conventional criteria. However when total perinatal wastage was calculated, the figure was 46.5/1000, suggesting excess deaths early in pregnancy and beyond the first week of life in twin pregnancies in general.
authors.forename: T
authors.initials: T
authors.lastname: Agustsson
authors.forename: R T
authors.initials: RT
authors.lastname: Geirsson