The association between timing in pregnancy of drought and excess rainfall, infant sex, and birthweight: Evidence from Nepal - PubMed (original) (raw)
The association between timing in pregnancy of drought and excess rainfall, infant sex, and birthweight: Evidence from Nepal
Nadia G Diamond-Smith et al. Environ Epidemiol. 2023.
Abstract
Background: Past research on the impact of climatic events, such as drought, on birth outcomes has primarily been focused in Africa, with less research in South Asia, including Nepal. Existing evidence has generally found that drought impacts birthweight and infant sex, with differences by trimester. Additionally, less research has looked at the impact of excess rain on birth outcomes or focused on the impact of rainfall extremes in the preconception period. Using data from a large demographic surveillance system in Nepal, combined with a novel measure of drought/excess rainfall, we explore the impact of these on birthweight by time in pregnancy.
Methods: Using survey data from the 2016 to 2019 Chitwan Valley Study in rural Nepal combined with data from Climate Hazards InfraRed Precipitation with Station, we explored the association between excess rainfall and drought and birthweight, looking at exposure in the preconception period, and by trimester of pregnancy. We also explore the impact of excess rainfall and drought on infant sex and delivery with a skilled birth attendant. We used multilevel regressions and explored for effect modification by maternal age.
Results: Drought in the first trimester is associated with lower birthweight (β = -82.9 g; 95% confidence interval [CI] = 164.7, -1.2) and drought in the preconception period with a high likelihood of having a male (odds ratio [OR] = 1.41; 95% CI = 1.01, 2.01). Excess rainfall in the first trimester is associated with high birthweight (β = 111.6 g; 95% CI = 20.5, 202.7) and higher odds of having a male (OR = 1.48; 95% CI = 1.02, 2.16), and in the third trimester with higher odds of low birth weight (OR = 2.50; 95% CI = 1.40, 4.45).
Conclusions: Increasing rainfall extremes will likely impact birth outcomes and could have implications for sex ratios at birth.
Keywords: Birthweight; Drought; Excess rainfall; Food security; South Asia.
Copyright © 2023 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The Environmental Epidemiology. All rights reserved.
Conflict of interest statement
The authors declare that they have no conflicts of interest with regard to the content of this report. Support for this research was provided by core center grant P30-ES030284 from the National Institute of Environmental Health Sciences, National Institutes of Health. Ethical approval for the collection of birth outcome data was provided by the Nepal Health Research Council and the University of Michigan. Data from the Chitwan Valley Family Study are available for public and restricted use through the Data Sharing for Demographic Research repository at ICPSR (https://www.icpsr.umich.edu/web/DSDR/series/646). CHIRPS precipitation data are publicly available at https://www.chc.ucsb.edu/data/chirps.
Figures
Figure 1.
Conceptual model of pathways of focus between precipitation and low birthweight.
Figure 2.
Map of the Chitwan Valley Family Study area. Source: OpenStreetMap.
Figure 3.
Effect modification by maternal age for the association between drought and birthweight.
References
- WHO. Global Nutrition Targets 2025: Low Birth Weight Policy Brief. World Health Organization; 2014. Available at: https://apps.who.int/iris/bitstream/handle/10665/149020/WHO_?sequence=2
- Hack M, Taylor HG, Drotar D, et al. Chronic conditions, functional limitations, and special health care needs of school-aged children born with extremely low-birth-weight in the 1990s. JAMA. 2005;294:318–325. -PubMed
- Mu M, Wang SF, Sheng J, et al. Birth weight and subsequent blood pressure: a meta-analysis. Arch Cardiovasc Dis. 2012;105:99–113. -PubMed
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