Oesophageal atresia in twins.

The twin incidence is higher in infants with oesophageal atresia (OA) than in the general population. The purpose of this study was to review the twin OA information from five institutions and evaluate possible links between the development of OA and the twinning process. Data were compared, combined, and analysed. There was a total of 1,215 infants with OA, of whom 50 were from a twin pregnancy and 1 from a triplet pregnancy. Two sets of twins were concordant for OA. Mean birth weights and gestational ages were lower in the twin infants (P < 0.0005) and survival was lower in twins (65%, P < 0.005) than singletons. The anatomical variant of pure OA without fistula was seen in proportionally fewer twins (4%) than in singletons (7%). Multiple anomalies were present in 40% of twins compared with 33% of singletons, although this did not reach statistical significance. OA in our multicentre population was more common in twins. Several possible mechanisms are put forward to explain the apparent link between twinning and OA. Further analysis of this aspect of OA may aid in understanding the aetiology of this congenital anomaly.