Does the respiratory distress syndrome in twins and singletons run different risks of persistent ductus arteriosus?

The incidence and evolution of patent ductus arterioses (PDA) was evaluated in twins and preterm singletons with birth weigth ≤ 1750 g admitted to our Department in 1987 for respiratory distress syndrome (RDS). Screening by echocardiography and Doppler-flow studies (AT MK 600) was performed on the third day of life. Out of 91 neonates who needed intubation and ventilation during this 12-month period (23.8% of admissions), 40 weighed less than 1750 g and of these 40, 14 were twins (35%). Hemodynamically significant PDA was documented in 13 patients; of these, only 5 were preterm singletons and 8 were twins. Two twins weighing < 1000 g received no therapy for ductus closure; one ductus closed spontaneously, the other had an early demise. Three twins and 2 preterm singletons received indomethacin; one of the twins needed a second cycle for definitive ductus closure. Three twins and three preterm singletons underwent surgery, while one twin died on the 10th postoperative day. Screening and early therapy of PDA during RDS could be of great clinical importance. Twinning seems to play a role in the incidence and evolution of PDA and this needs to be evaluated in further studies.