Experiences of an earthquake during pregnancy, antenatal mental health and infants' birthweight in Bhaktapur District, Nepal, 2015: a population-based cohort study.

Background: Infant birthweight is an important public health indicator that is a proxy of maternal and baby's health. Earthquakes can cause acute distress, but can also contribute to chronic stress through long-term disruptions to social, economic and domestic circumstances. The aims of this study were to examine the direct effect of earthquake experiences on the birthweight of infants of women who experienced the 2015 Nepal Earthquakes during pregnancy and whether mental health mediated this relationship.

Methods: This is a prospective, population-based cohort study. Pregnant women in Bhaktapur District, Nepal who had experienced the 2015 earthquakes after conception were recruited. Baseline data were collected in structured individual interviews. Follow up was a short telephone interview two weeks after the baby's birth. Infant birthweight recorded on the hospital-issued birth certificate. The direct effect of earthquake experiences on birthweight and the indirect effect via antenatal common mental disorders (CMDs) were tested using Sobel tests simultaneously.

Results: In total 497/498 women contributed baseline data and 469 (94.4%) women also provided the birth weight of their infants. In total 6% of infants had low birth weight (< 2.5 kg). The earthquake experiences did not have a significant direct effect on birthweight (p = 0.116). However, the effect of earthquake experiences had a significant indirect effect on infant birthweight via CMDs. When 15 covariates were controlled, women who had moderate to severe earthquake experiences had an increase of 1.58 scores of antenatal CMD symptoms that resulted in their babies being 20.50 g lighter than those who had low earthquake experiences (p = 0.026).

Conclusions: The findings from this study indicate that the relationship is mediated by the mental health of women during pregnancy. Data demonstrate that the mental health of women who are pregnant should be prioritised in post-disaster management not only because of the burden experienced by women but also because of the risk for the growth and development of their babies.