Antenatal corticosteroids and newborn screening for congenital adrenal hyperplasia

Objective: To assess the effect of reported corticosteroid exposure on neon atal levels of 17-hydroxyprogesterone (17-OHP), the cortisol precursor used in newborn screening for congenital adrenal hyperplasia, in newborns weigh ing less than 2500 g at birth. Design: A retrospective study of newborns weighing less than 2500 g at birt h and exposed to corticosteroids as reported on their newborn screening car d compared with newborns weighing less than 2500 g at birth and reported as not exposed to corticosteroids. Methods: Birth weight, gestational age, age at screening, special care info rmation, and name of screening hospital were obtained from newborn screenin g cards for 16115 newborns screened in Michigan during the first 3 months o f 2000. Levels of 17-OHP, measured by fluoroimmunoassay, were obtained from Michigan's Newborn Screening Program database. Results: The mean 17-OHP level for the 69 low-birthweight newborns in the c orticosteroid-exposed group was 52 ng/mL, which was higher than that for th e 771 low-birth-weight newborns in the unexposed group (35 ng/mL) (P<.001). Reported corticosteroid use did not decrease the number of expected border line positive screening results for congenital adrenal hyperplasia (P>.05). Levels of 17-OHP varied by birth weight in corticosteroid-exposed and unex posed newborns. Conclusions: Corticosteroid exposure may not suppress screening 17-OHP leve ls. Therefore, newborn screening should not be delayed in premature newborn s because of antenatal exposure to corticosteroids.