Increased Vulnerability to Dehydration Due to Heat Stress and Drought Across Reproductive States for Pastoralist Women in Northern Kenya

OBJECTIVES: Extreme weather events, like drought and heat stress, make it harder to meet water needs in water-insecure settings, particularly vulnerable groups. This study examines how short-term (heat stress) and long-term (drought) water stress affects hydration status across reproductive states (pregnant, lactating, compared to non-pregnant/non-lactating) for Daasanach semi-nomadic pastoralist women in northern Kenya. METHODS: Drawing on unbalanced panel data, we analyzed 565 observations from 303 women (aged ≥ 16 years) in 2019-2024. Hydration was assessed via urine specific gravity (USG) with dehydration classified as USG > 1.020. Environmental heat stress was measured by ambient temperature and humidity, with sensitivity analyses using wet bulb globe temperature. RESULTS: Mixed effect logistic regression models indicated ambient temperature and humidity were significantly associated with greater odds of dehydration across all women. Holding heat stress constant, lactating but not pregnant women had higher odds of dehydration than non-pregnant/non-lactating women. A significant interaction between heat stress and reproductive status indicated that the probability of dehydration increased fastest for pregnant women as temperatures rose. Holding heat constant, dehydration probability increased during drought years compared to pre- and post-drought and was most pronounced among lactating women. CONCLUSIONS: Ambient heat stress increases dehydration risk among Daasanach women with effects compounded in pregnancy, though overall lactation was the period of greatest vulnerability to dehydration. Dehydration probability peaked during the drought illustrating how long-term periods of water scarcity also challenge water needs. Heat stress and droughts exacerbate maternal and infant health risks; thus, targeted hydration and cooling interventions are needed.