We analyzed validity of the New Ballard Score, performed from 30 minutes to 96 hours of age. Our studies showed that, overall, the score was equally valid when performed anytime between 30 minutes and 96 hours of postnatal age. When infants less than 26 weeks were analyzed separately, the validity deceased after 24 hours of extra uterine life.
Correlation coefficients were r => 0.96 at all postnatal ages when all gestational ages were taken together. When infants < 26 weeks gestational age were analyzed separately however, correlation fell to 0.75 after 24 hours of life. This taught us that, where extremely premature infants are concerned, it is best to perform the assessment prior to 24 hours of postnatal age.