Birth outcomes of patients with isolated anorectal malformations: A population-based case-control study.

In most patients affected by isolated anorectal malformation (IARM) the etiology is largely unknown. Thus, the aim of our project was to analyze possible risk factors for IARM. In the first step, birth outcomes of cases with IARM were analyzed on the basis of maternal socio-demographic variables, and these data are presented in this paper. Gestational age at delivery, birthweight, preterm birth, low birthweight and small for gestational age of cases with IARM were evaluated in the function of maternal age, birth/pregnancy order, marital and employment status of mothers in the population-based large dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996. The study samples included 231 live-born cases with IARM, 361 matched and 38 151 population controls without any defect. IARMs are more frequent in males, twins and newborn infants with low birthweight and small-for-gestational-age, the latter being the consequence of intrauterine growth restriction. In addition, mothers of cases were younger but with higher birth order, and had lower socio-economic status. These maternal variables are characteristic for the gypsy population in Hungary. The higher proportion of gypsy women among the mothers of cases with IARM was confirmed during the home visits of the study. Male sex and intrauterine growth restriction of cases, in addition to low socioeconomic status and gypsy origin of mothers may have a role in the risk of IARMs.