Impact of prenatal diagnosis of transposition of the great arteries on obstetric and early postnatal management.

Objectives: A growing percentage of cases of transposition of the great arteries (TGA) are being diagnosed prenatally. A decrease in the percentage of spontaneous deliveries has been reported, but the rate of cesarean section (c-section) in this population has never been studied. Our goal was to determine whether prenatal diagnosis affects delivery and immediate neonatal management of TGA neonates.

Study Design: A series of 121 TGA arterial switch candidates were included over a 6-year period. Variables on delivery, clinical status at ICU admission, arrival time and atrial septostomy were recorded retrospectively. Comparisons between the two groups were made by Student's t or Chi-squared test.

Results: A cohort of 121 patients was enrolled (48 prenatal and 73 postnatal diagnoses). Induced delivery and c-section were more frequent in the prenatal (54.1% and 31%) than in the postnatal diagnosis group (19.4% and 8%; p<0.0002 and p<0.001, respectively). The mean interval between birth and ICU admission was 2h 30 min in the prenatal compared to 26 h in the postnatal diagnosis group (p<0.001). Arrival times were similar in both groups. Atrial septostomy by umbilical route was more often feasible in the prenatal (81%) than in the postnatal diagnosis group (51%; p<0.001), with a higher rate of failure in the latter.

Conclusion: Prenatal awareness of TGA was associated with a higher percentage of induced deliveries and a major increase in the rate of c-section, without any impact on the newborn except easier umbilical atrial septostomy and earlier ICU admission.