The goal of our study was to characterise the relationships between trait anxiety symptoms of women during their pregnancies and birth outcomes of their offspring using a longitudinal cohort from the Maternal Health Practices and Child Development Project. We used the State-Trait Personality Index anxiety measure that is based on Spielberger's State-Trait Anxiety Inventory to measure self-reported trait anxiety at two gestational assessments (fourth and seventh months, representing the first and second trimesters, respectively) and at a third assessment shortly after delivery (representing the third trimester). Demographic, social, psychological, substance use and medical factors were assessed prenatally, and outcomes of the 763 live, singleton births were determined at delivery.
In regression models, trait anxiety at the second and third trimesters predicted lower birthweight and shorter birth length, controlling for confounders. Anxiety reported at the third trimester predicted shortened gestational age, controlling for confounders. At the first and second trimesters, the relationship of birthweight and birth length to maternal trait anxiety was only significant for severe anxiety. Women whose anxiety reached severe levels for at least two trimesters were significantly more likely to deliver offspring of lower birthweight and shorter birth length than those women who reported severe anxiety at none or only one of the trimesters. Additionally, offspring of women who experienced severe anxiety during all three trimesters had shorter mean gestational age than offspring of women who did not report severe anxiety at any trimester. Women who report chronic, severe trait anxiety are at the highest risk of having shorter gestations and delivering smaller babies.