Main Findings
Infants of mothers reporting severe anxiety symptoms in the 17th gestational week were more likely to have lower birth weight than infants born to mothers with very light anxiety symptoms or none at all. This association was reduced, but remained, after adjusting for shared family factors as well as smoking and alcohol consumption. However, in the sibling subsample, once socio-demographic variables were controlled for, the association was no longer significant. In regard to prenatal anxiety and gestational age, there wass no significant change before and after family adjustment. After multiple imputations, maternal anxiety at week 30 in pregnancy was significantly associated with shorter gestational age.