Cephalocaudal progression of neonatal jaundice assessed by transcutaneous bilirubin measurements

The cephalocaudal progression in neonatal jaundice is a well-known phenomenon. Since transcutaneous bilirubin measurements (TcB) are increasingly applied, for which different body site can be used, we aimed to quantify the cephalocaudal progression of neonatal jaundice through TcB and to assess the influence of gestational age, postnatal age and the degree of hyperbilirubinemia on this cephalocaudal progression.

In jaundiced neonates ≥32 weeks of gestational age, TcB was measured on 5 sites: forehead, sternum, hipbone, proximal tibia and foot, during the first two weeks of life.

58 neonates were included. Mean ratios of TcB on the 5 sites compared to the forehead were: sternum 1,03 (SD 0,14), hipbone 0,80 (SD 0,16), proximal tibia 0,63 (SD 0,14) and foot 0,44 (SD 0,15). Gestational age, postnatal age nor the degree of hyperbilirubinemia were associated with the cephalocaudal progression (ANOVA p > 0,05).

The cephalocaudal progression of neonatal jaundice is evident, with caudal levels of TcB being less than half of cephalic measurements. This implicates that TcB measurements caudal from the sternum are less reliable, and should be avoided. The degree of cephalocaudal progression is not associated with gestational or postnatal age, nor with height of bilirubin levels.