title: A low pregnancy body mass index is a risk factor for an offspring with gastroschisis.
abstract: A mother's prepregnancy obesity has been suggested as a risk factor for having offspring with an abdominal wall defect. We evaluated this hypothesis among 104 cases of gastroschisis--a severe birth defect of the abdominal wall most prevalent in infants of young women--and 220 controls with no defect. Using Quetelet's index (QI = weight in kg/height in m2) as a measure of body mass, we found a higher risk of gastroschisis (odds ratio (OR) = 3.2; 95% confidence interval (CI) = 1.4-7.3) for underweight mothers (QI<18.1 kg/m2) and a lower risk (OR = 0.2; 0.05-0.9) for overweight mothers (QI>28.3 kg/m2) as compared with mothers of normal weight. As QI was correlated to height, with the correlation varying according to mother's ethnicity and age, we adjusted for these factors in the analysis; the adjusted values approximated the unadjusted values. Evaluation of QI as a continuous variable showed that, for every unit increase in QI, the risk for gastroschisis decreased by about 11%. Sociodemographic, pregnancy, and nutrient factors did not confound the association. These results suggest that low prepregnancy body mass rather than obesity is a risk factor for gastroschisis.
authors.affiliation: California Birth Defects Monitoring Program, Emeryville 94608-1811, USA.
authors.forename: P K
authors.initials: PK
authors.lastname: Lam
authors.forename: C P
authors.initials: CP
authors.lastname: Torfs
authors.forename: R J
authors.initials: RJ
authors.lastname: Brand
mesh_terms: D000328:Adult; D015992:Body Mass Index; D002140:California / Q000453:epidemiology; D005260:Female; D020139:Gastroschisis / Q000453:epidemiology*; D006801:Humans; D007231:Infant, Newborn; D015999:Multivariate Analysis; D016017:Odds Ratio; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors