Depressive symptoms during pregnancy and low birth weight at term: longitudinal study.

There is conflicting evidence regarding the effect of depression during pregnancy on birth weight. We used data from the Avon Longitudinal Study of Parents and Children to investigate whether depressive symptoms during pregnancy in 10,967 women led to low birth weight at term in their offspring. Those with a high depressive symptom score during pregnancy were more likely to have babies of low birth weight (95% CI 1.16-2.40, P<0.01), but this attenuated after adjustment for confounders (OR=1.29,95% CI 0.87-1.91, P=0.210). Hence there is little evidence of an independent association between depressive symptoms during pregnancy and birth weight.