Effect of gender, birth weight and gestational age on serum 17-hydroxyprogesterone concentration and distribution among neonates in Saudi Arabia.

Blood samples from 813 newborns were spotted on to filter paper and the 17-hydroxyprogesterone concentration was measured using the Delfia (R) fluorometric immunoassay. The median, mean, and standard deviation (SD) for the total population were 20, 21 and (11) nmol/L respectively. Males had significantly higher levels than females with median, mean and (SD) of 22, 22 and (12) nmol/L. Similarly, low birth weight babies were found to have significantly higher levels than normal birth weight babies with median, mean and (SD) of 21, 24 (12) nmol/L. Preterm babies were also found to have significantly higher levels than full term babies, with median, mean and (SD) of 25, 29 (16) nmol/L. As experienced elsewhere, those factors should be taken into consideration when considering a cut-off point in any neonatal screening program for congenital adrenal hyperplasia.