Effects of prenatal and postnatal maternal emotional stress on toddlers' cognitive and temperamental development.

BACKGROUND: Maternal stress is associated with impairments in the neurodevelopment of offspring; however, the effects of the timing of exposure to maternal stress on a child's neurodevelopment are unclear.

METHODS: In 2010, we studied 225 mother-child pairs in Shanghai, recruiting mothers in mid-to-late pregnancy and monitoring offspring from birth until 30 months of age. Maternal stress was assessed prenatally (at 28-36 weeks of gestation) and postnatally (at 24-30 months postpartum) using the Symptom-Checklist-90-Revised Scale (SCL-90-R) and Life-Event-Stress Scale to evaluate mothers' emotional stress and life event stress levels, respectively. Children's cognition and temperament were assessed at 24-30 months of age using the Gesell Development Scale and Toddler Temperament Scale, respectively. Multi-variable linear regression models were used to associate prenatal and postnatal stress with child cognitive and temperamental development.

RESULTS: Maternal prenatal and postnatal Global Severity Index (GSI) of SCL-90-R were moderately correlated (ICC r=0.30, P<0.001). After adjusting for relevant covariates, the increase in prenatal GSI was associated with decreases in toddlers' gross motor, fine motor, adaptive and social behavior development independently of postnatal GSI, while the increase in postnatal GSI was associated with changes in multiple temperament dimensions independently of prenatal GSI. The effects of prenatal and postnatal depression scores of SCL-90-R were similar to those of GSI.

LIMITATION: Relatively small sample size.

CONCLUSIONS: Compared with postnatal exposure, children's cognitive development may be more susceptible to prenatal exposure to maternal emotional stress, whereas temperamental development may be more affected by postnatal exposure to maternal emotional stress compared with prenatal exposure.