Seasonal Temperature Variations and Neonatal Dehydration Requiring Medical Support

Neonatal weight loss of up to 10%, immediately after birth––peaking around 3-4 days of life––is a well-recognized phenomenon. Factors such as inadequate milk supply in the initial days, improper feeding techniques, and high ambient temperatures can exacerbate this issue. In vitro studies indicate that high temperatures (39°C) can enhance lactation, while prolonged exposure to 41°C can reduce milk production. These findings suggest that ambient temperature could significantly influence the development of postnatal dehydration.

A new study aimed to compare the incidence and severity of postnatal dehydration during warmer and cooler months.

This was a prospective study that assessed the impact of ambient temperature on severe dehydration in term neonates, from July 2021 to June 2022. The study included neonates delivered at term and admitted with severe dehydration to the neonatal intensive care unit of JSS Hospital, Mysuru. Severe dehydration was defined as cumulative weight loss > 10% of birth weight, weight loss (<10%) with hypernatremia, and/or increased blood urea. Septic newborns and those with congenital malformations were excluded.

Overall, 55 neonates out of 941 NICU admissions (5.8%) were admitted with significant weight loss. Of these, 26 (47.2%) were admitted in cooler months and 29 (52.7%) in warmer months. It was noted that 47 (85.4%) neonates had hypernatremia – 5 (9%) had very high sodium levels (>170 mmol/L), 25 (45.4%) had fever, 9 (16.3%) had hypoglycemia, and 8 (14.5%) had decreased activity. The median weight at admission was 2,540 g in cooler months and 2,720 g in warmer months. The median weight loss was 400 g in cooler months compared to 480 g in warmer months – a difference that was not statistically significant. Further, the incidence of dehydration requiring medical support in the immediate postnatal period was 5.8%, with no significant difference between cooler and warmer months.

From the results, it was concluded that the incidence of significant dehydration does not differ markedly between cooler and warmer months. Dehydration requiring medical support is common in both cooler and warmer months, with slightly (statistical insignificant) higher severity in warmer months.

Source: Krishnegowda S, Thandaveshwara D, Doreswamy SM. Indian Pediatrics. 2024 May;61(5):460-2.