Recurrence of mild malformations and dysplasias

OBJECTIVE: To estimate whether women delivering infants with mild malformations are at increased risk to have a subsequent infant with a mild malformation. METHODS: Both severe and mild malformations detected at birth were cataloged prospectively for 33,701 women with two consecutive singleton births of infants weighing 500 g or more at a tertiary care hospital. Records from a total of 67,402 infants were analyzed from January 1, 1988, through December 31, 2000. Mild malformations and dysplasias were defined to include skin lesions (eg, café au lait spots, nevi, and hemangiomas), extra nipples, and abnormalities involving digits. Pearson and McNemar χ² statistics and analysis of variance were used for statistical analysis. Estimation of recurrence risks was accomplished using standard methods for rates and proportions. RESULTS: Of the study women, 2.7% delivered infants with mild malformations in their index pregnancy. Mild malformations recurred in 7% of women whose index infant had a mild malformation (2.7% versus 7%, P < .001). Mild malformations involving the skin or digits also significantly increased in the next delivery (2% versus 5%, P < .001; 0.5% versus 8%, P < .001; recurrence of skin and digit anomalies, respectively). CONCLUSION: Women delivering infants with mild malformations involving the skin and digits of the infant are at increased risk for recurrence during their next pregnancy.