Aim: To determine what proportion of newborns with critical heart defects are discharged undiagnosed from the maternity ward.
Methods: Data were retrieved retrospectively for infants born in our referral area from 1993 to 2001 and undergoing surgical or catheter-based intervention before 2 mo of age because of critical heart defects.
Results: 259 full-term infants had critical heart defects. Duct-dependent systemic circulation was present in 129, duct-dependent pulmonary circulation in 106, and 24 infants were not duct dependent but critically ill. In 51 infants (20%) the heart defect was not suspected before discharge from the maternity ward. Such late detection occurred more often in infants with duct-dependent systemic circulation (30%) and in children with defects that were not duct dependent (38%) than in children with duct-dependent pulmonary circulation (4%) (p<0.001). The proportion detected after discharge from the maternity ward increased from 13% in 1993-1995 and 21% in 1996-1998 to 26% in 1999-2001 (p<0.05).
Conclusion: Many infants with critical congenital heart defects are not diagnosed before discharge from the neonatal maternity ward. The proportion discharged undiagnosed has increased. Neonatal screening fails mainly in children with duct-dependent systemic circulation.