Some aspects of the epidemiology of human minor birth defects and morphological variants in a completely ascertained newborn population (Madison study)

Abstract

In 4319 infants examined at birth who were without major birth defects those with a “remarkable” pregnancy outcome, i.e., low birth weight ( <2500 g). long gestation ( ≥ 43 weeks), stillborn, or twin status, were more likely to have a minor birth defect than the remainder. With regard to the 2 most frequent defects, simian crease and folded helix, the increase in the former was of about the same order (1.6–2.1‐fold) in those with remarkable outcome of all types, but the increase in the latter was particularly great in twins (∼︁ 3.1‐fold) compared with the other remarkable outcomes (∼︁ 1.3‐fold). With regard to variants, which were defined as those features scored that occurred in 4% or more of the newborn population, some (flat and small hemangioma on face and scalp, Brushfield spots, flat nasal bridge, hyperflexed thumbs, hydrocele, and mild calcaneovalgus) exhibited a trend towards negative association with low birth weight and a trend to positive association (with exception of hemangioma and calcaneovalgus) with long gestation, suggesting they may simply be indirect markers of gestational age. There was a trend to a slight decrease in the frequency of minor defects with increasing maternal age, similar to the trend for major defects.