Effect of High Ambient Temperature Exposure Risk and Vulnerability on Pre-Eclampsia During Late Pregnancy in Nepal- Prospective Cohort Design

Little is known on the high ambient temperature risk and vulnerability on pre-eclampsia during late gestation despite evidence on biological plausibility in low resource setting like Nepal. Using a large-scale cohort from Nepal, we examined the risk and vulnerability of heat events on pre-eclampsia during late pregnancy. Using a prospective cohort of late gestation women ( n = 98,560), we compared those women who were diagnosed of pre-eclampsia with those who did not have pre-eclampsia and assessed the prior 7-day ambient temperature exposure to the cohort. We used the distributed lag non-linear model framework to assess the exposure response and exposure lag response for 7 days after exposure to heat events (≥ 75 centile). We assessed the vulnerability of heat events based on the social positioning (ethnicity) and adjusted with other co-variates. Of the cohort, 1.12% of the women had pre-eclampsia during late gestation. When the cohort was exposed to extreme heat ≥ 95 centile, adjusted cumulative odds of pre-eclampsia increased by 42% (adj-cum-OR = 1.42; 95%CI; 1.05–1.93). In terms of the exposure (≥ 95 centile) lag to overall population, the adjusted odds of pre-eclampsia increased from lag-day 1 (adj-cum-OR = 1.02) to lag-day 3 (adj-cum-OR = 1.40) and then decreased in subsequent lag. In terms of vulnerability of pre-eclampsia due to social positioning to heat, the adjusted cumulative odds of pre-eclampsia among socially advantaged groups increased non-significantly by 3% (adj-cum-=1.03; 95%CI; 0.61,1.74). While the cumulative odds of pre-eclampsia among socially disadvantaged groups increased by 61% (adj-cum-OR = 1.61; 95%CI; 1.11, 2.36). Evidence from cohort study showed risk of heat on pre-eclampsia and increased vulnerability due to social positioning, indicating the need for heat adaptation pregnancy care guideline.