Association between social position and congenital anomalies: a population-based study among 19,874 Danish women

To examine the association between maternal and paternal educational level and household income and the risk of giving birth to a baby with a congenital anomaly in a population of Danish women.

We performed a population-based cohort study, based on record linkage of data from Danish administrative registries. For each pregnant woman in the cohort, we described financial and educational resources and congenital anomalies in her offspring. We used logistic regression to model the association between social position and congenital anomalies.

The analyses included all 19,874 primiparous singleton deliveries in North Jutland county, Denmark, from 1991 to 1998. There were 1025 (5.2%) babies with congenital anomalies. The odds ratios (ORs) for giving birth to a baby with a congenital anomaly showed a dose- response decline, as the mothers' educational level increased. Women with less than 10 years of schooling had an almost three-fold increased risk of giving birth to an infant with a congenital anomaly, as compared with women with more than 4 years of higher education (OR=2.9, 95% confidence interval = 1.8-4.6). Paternal educational level and household income were, to a lesser degree, associated with congenital anomalies in the offspring.

Maternal educational level, and to a lesser degree paternal educational level and household income, were associated with the risk of giving birth to a baby with a congenital anomaly. However, the analysis did not take into account maternal health status, and the results might be due to differential misclassification or residual confounding.