Preconception stressful life events predict low infant birthweight among women in the United States

OBJECTIVE: To determine if and to what extent maternal exposure to stressful life events (SLEs) prior to conception was associated with subsequent infant birthweight using a nationally representative sample of U.S. women.

METHODS: We examined 8,700 mothers and infants participating in the Early Childhood Longitudinal Study-Birth Cohort. We defined exposure to SLEs as maternal report of death of a parent or previous child, divorce, being separated or widowed, or fertility problems prior to conception. Weighted regressions estimated the effect of exposure on very low (VLBW; <1,500 grams) and low (1,500-2,499 grams) birthweight, adjusting for maternal sociodemographic and health factors and stress during pregnancy.

RESULTS: 19.4% of women experienced any SLE prior to conception. In adjusted analyses, women who experienced any SLE prior to conception were 40% more likely to have a VLBW infant than women who did not (OR 1.40; 95% CI: 1.14-1.72). Furthermore, the accumulation of SLEs was associated with reduced infant birthweight.

CONCLUSIONS: This is the first nationally representative study to investigate the impact of SLEs prior to conception on infant birthweight in the U.S. Exposure to SLEs prior to conception increases the risk for having a VLBW infant. The effect of exposure to SLEs may accumulate over a woman's lifecourse to increase her risk for having a lower birthweight infant. Interventions to improve birth outcomes will need to shift the clinical practice paradigm upstream to the preconception period to reduce the impact of exposure to stress over the lifecourse and improve the long-term health of children.