17-hydroxiprogesterone values in healthy preterm infants

Introduction: In preterm newborn, problems with the interpretation of 17-OHP may occur. Objective: Evaluate 17-OHP values in healthy preterm newborns until they reach the corrected gestational age. Methods: Longitudinal study of 36 preterm infants with 17-OHP evaluation using ELISA from heel blood from 3 to 5 days and thereafter every 2 weeks until the corrected gestational age. Values adjusting multiple variables such as gestational age, birth weight and sex, among others were compared. The results were analyzed against 82 healthy full-term infants. Results: In the first week of life, early term infants born within less than 34 months of gestational age show 17-OHP values that are much higher than the full term neonates. After a week, the values decrease and stabilize, but are still higher than those of full term neonates and remain so even at the corrected gestational age (average difference of 63.0%, CI 95%: 11.8%-115.5%). 33.6% (41 samples) of a total of 122 samples taken from preterm infants were higher than 30 ng/mL. Conclusions: 17-OHP values in early term infants are higher than those in full term neonates and can be related to postnatal adaptive processes. It is suggested that a second screening at the 37th week of corrected age be performed.