Abstract 17

Aims: To quantify the occurrence rate of ventricular septal defect (VSD) in a population of clinically normal neonates and to define any associated risk factors.

Patients: 142 patients with VSDs in a "scanned" population of 3344 neonates (Nov. '94-Jun. '97). Echocardiograms were performed at approximately 48 hours post delivery. Infants at higher risk of congenital heart disease were excluded as were those with a cardiac abnormality on clinical examination. Patients were compared with a control group of clinically normal neonates who also had a normal scan.

Results: VSDs were detected in 4.25% of the group undergoing echocardiography. 8/142 had perimembranous defects and the remainder muscular lesions. 10 neonates had multiple defects. The groups showed no significant difference in birthweight or maternal age. Neither maternal smoking nor alcohol ingestion influenced VSD rates. A maternal history of previous miscarriage was more common in the VSD group; (31 compared to 23 controls) as was the number of para 0 mothers (p>0.05).

Conclusion: The occurrence rate of VSD in this neonatal population is higher than might be expected, given the exclusion of "high risk" infants. There is no evidence that maternal smoking or alcohol ingestion increases the risk of VSD. The data on any link between low parity/miscarriage rate and VSD are as yet, inconclusive.