BACKGROUND: The goal was to study the effects of social support during pregnancy on maternal depressive symptoms, quality of life and pregnancy outcomes. METHODS: Eight hundred ninety-six women were prospectively studied in the first trimester of pregnancy and following completion of the pregnancy. The sample was divided into quartiles yielding groups of low, medium and high social support based on perceived social support. RESULTS: Pregnant women with low support reported increased depressive symptoms and reduced quality of life. The effects of social support on pregnancy outcomes were particularly pronounced in women who had smoked during pregnancy, with significant main effects of social support in a two-way analysis of variance (smoking status and social support) for child body length (F = 4.26, P = 0.04; 50.43 +/- 2.81 cm with low support versus 51.76 +/- 2.31 cm with high support) and birthweight (F = 11.35, P = 0.001; 3175 +/- 453 g with low support versus 3571 +/- 409 g with high support). In smokers, pregnancy complications occurred more frequently when given low support {34 versus 10.3% with high support, chi(2) = 5.49, P = 0.019; relative risk (RR) = 3.3 [95% confidence interval (95% CI) = 1.1-10.2]}, and the proportion of preterm deliveries was greater given low support (10.0 versus 0% with high support, chi(2) = 3.84, P = 0.05, odds ratio = 8.1). CONCLUSIONS: Lack of social support constitutes an important risk factor for maternal well-being during pregnancy and has adverse effects on pregnancy outcomes.
