Transepidermal water loss in infants born at 24 and 25 weeks of gestation.

The rate of evaporation of water from the skin of 13 infants born at 24 (n=3) and 25 (n=10) weeks of gestation was measured on the first day after birth and at postnatal ages of 1, 3, 7 and 28 d, using the gradient method. Transepidermal water loss was estimated from this rate and corrected to an ambient relative humidity (RH) of 50%. Transepidermal water loss, corrected to 50% RH, was high on the first day after birth (58.4+/-14.8 g m(-2) h(-1)) and remained at the same level during the second day (59.3+/-17.6 g m(-2)h(-1)). It then decreased significantly to 43.8+/-9.5 at a postnatal age of 3 d, 36.1+/-12.6 at 7 d and 24.2+/-7.7 g m(-2) h(-1) at 28 d (p < 0.001). Within the group investigated, there was no significant correlation between transepidermal water loss and body or skin temperature, birth weight, gender, mode of delivery or gestational age. Transepidermal water loss on the first day after birth was somewhat lower than the highest losses previously found in infants born at 25 weeks of gestation, and of the same magnitude as previously reported for infants born at 25-27 weeks. Transepidermal water loss at postnatal ages of 1, 3, 7 and 28 d in the present study was higher than that previously found in the group of infants born at 25-27 weeks. In conclusion, in infants born at 24-25 completed weeks of gestation transepidermal water loss was high immediately after birth and decreased with increasing postnatal age, but at a slower rate than previously reported for slightly more mature infants.