Abstract
Objective Determination of gestational age and/or birth weight at which sacral ossification centers appear.
Study Design Radiographs were reviewed of newborns admitted to Auckland City Hospital between January 2008 and December 2010. Infants were divided into weight clusters increasing in 100-g increments from 400 g to 3000 g and 500-g increments thereafter, for a total of 29 weight clusters. Adequate images were available for at least five newborns per cluster.
Results Images of 163 newborns were reviewed. All but six newborns had five sacral ossification centers by 32 weeks' gestation and a birth weight of 1800 g. Five of the six infants had a congenital anomaly and associated growth restriction.
Conclusions Infants can be expected to have all five sacral ossification centers present by the time they reach a gestational age of 32 weeks and/or a birth weight of 1800 g. Variation from this can be associated with congenital anomalies and growth restriction.
Keywords
sacral ossification - newborn - spinal ultrasonography - growth restriction - congenital anomaly
