Objective: To determine if a healthy newborn’s age in hours (3, 6, or 9 hours after birth) affects thermoregulatory status after the first bath as indicated by axillary and skin temperatures.

Design: Quasi-experimental, mixed-model (between subjects and within subjects) design with hours of age as the nonrepeated variable and prebath and postbath temperatures as the repeated variables.

Setting: Family-centered care unit at an urban hospital in the southwestern United States.

Participants: Healthy newborns (N = 75) 37 weeks or more completed gestation.

Methods: Mothers chose time of first bath based on available time slots (n = 25 newborns in each age group). Research nurses sponge bathed the newborns in the mothers’ rooms. Axillary temperature, an index of core temperature, was measured with a digital thermometer, and skin temperature, an index of body surface temperature, was measured with a thermography camera. Temperatures were taken before the bath; immediately after the bath; and 5, 30, 60, and 120 minutes after the bath. Immediately after the bath, newborns were placed in skin-to-skin care (SSC) for 60 or more minutes.

Results: We found a difference (p = .0372) in axillary temperatures between the 3- and 9-hour age groups, although this difference was not clinically significant (0.18 °F [0.10 °C]). We found no statistically significant differences in skin temperatures among the three age groups. Regardless of age group, axillary and skin temperatures initially decreased and then recovered after the bath.