Plastic Versus Cotton Caps for Preventing Hypothermia in Very Preterm Infants: A Randomized Clinical Trial

Preventing hypothermia in very preterm infants is difficult. This study aims to compare the effect of plastic versus cotton caps in combination with polyethylene body wrapping in the prevention of hypothermia in very preterm infants.

A total of 95 newborns less than 32 weeks of gestation were enrolled in this randomized clinical trial. Immediately after birth, the infants were placed in polyethylene covers. In the intervention group (n=48), the heads of newborns were covered with plastic caps, while in the control group (n=47), the heads were covered with cotton caps. The primary outcomes were temperature at admission and 1 hour after admission in the neonatal intensive care unit, as well as the rate of hypothermia in both groups.

Mean axillary temperature on admission was higher in the plastic cap group compared to the cotton cap group (P = .009). After adjusting for gestational age, the difference in mean admission temperature was higher in the plastic cap group in the 28-31 weeks' gestation (P = .013); however, all babies born at 25-27 weeks' gestation remained hypothermic at neonatal intensive care unit admission. The temperature 1 hour after admission was similar between the groups (P=.846). The rate of hypothermia showed no significant difference between groups.

Although plastic caps were associated with higher admission temperatures compared with cotton caps, they did not reduce the frequency of hypothermia. This points to the need for newer and combined strategies, especially in extremely preterm infants (25-27 weeks). Plastic caps remain a cost-effective and hygienic option for resource-limited settings. Trial registration: The trial was prospectively registered in the Iranian Registry of Clinical Trials (IRCT) under the registration number IRCT20091201002801N5 on February 9, 2023. The registration can be accessed at the following URL: https://irct.behdasht.gov.ir/trial/68485.