Baby's first bath: Changes in skin barrier function after bathing full-term newborns with water vs liquid baby cleanser

Background The impact of the newborn's first bath, whether given with water alone or water with skin cleansing products, on skin barrier function is unknown. Methods We evaluated skin barrier function, measured by skin surface pH (primary outcome), transepidermal water loss (TEWL), and hydration of the stratum corneum (SCH) in 100 newborns before and after their first bath, randomizing this cohort to bathing with water alone or with water and a liquid baby cleanser. Two consecutive measurements of each parameter were obtained at two anatomic locations, the volar forearm, and below the sternum. Randomization was by mode of delivery, with 50 vaginal and 50 cesarean section (C/S) delivered newborns. Results Skin pH decreased significantly following the first bath at both anatomic sites regardless of whether the bath was performed with water or with cleanser, and there was no significant effect on the change in pH in these two groups. Baseline TEWL and SCH measurements were significantly lower in the sternum area compared to the volar forearm. TEWL decreased significantly after the first bath except when the bath was given with water alone on the sternum site. SCH also decreased significantly after the first bath except in the forearm when the bath was given with water alone. Conclusions We conclude that skin surface pH, TEWL, and SCH all decrease significantly following the first bath, an indication of the development of skin barrier function in the newly born infant. In addition, bathing with water alone or water and a liquid baby cleanser does not impact the developing skin barrier.