RENO, NEV. — Preterm twins conceived through assisted reproductive techniques are more likely than twins conceived naturally to have respiratory distress syndrome and patent ductus arteriosus at delivery, investigators reported in a poster presentation at the annual meeting of the Society for Maternal-Fetal Medicine.
Nils Stenman, M.D., of the University of Pennsylvania, Philadelphia, and his colleagues compared neonatal outcomes of 238 preterm twins conceived using assisted reproductive techniques (ART) with those of 718 preterm twins that were naturally conceived. All twins were born at 24-35 weeks' gestation at one hospital over a 5-year period.
Mean birth weight and mean gestational age at delivery were the same for both groups of twins, as were rates of sepsis, necrotizing enterocolitis, intraventricular hemorrhage rates, and neonatal mortality.
However, the ART-conceived twins had a higher incidence of respiratory distress syndrome (70% versus 45%) and patent ductus arteriosus (63% versus 38%).
Mothers of the ART-conceived twins were more likely to be older, nulliparous, and white. However, there is no explanation for why the ART-conceived neonates would have a higher incidence of respiratory distress syndrome or patent ductus arteriosus, the researchers said.
A recent metaanalysis of studies of neonatal outcome in ART concluded that while singleton neonates conceived with ART tend to be born earlier and with lower birth weight and have worse outcomes, the same is not true for twins (BMJ [online] 2004;328:261). The studies in the analysis tended not to look as specifically at different neonatal outcomes in preterm twins as did the current study, or they looked at different outcomes, Dr. Stenman and colleagues said.
The neonatal mortality in the current study was 2% for both groups of twins.