Anterior fontanel size in Korean nursery newborns and clinical implications of large anterior fontanel: A retrospective cohort, observational study

Abstract

Anterior fontanel (AF) sizes in newborns are influenced by ethnicity, gender, genetics, nutrition, and other pathological conditions. However, AF sizes in recent Korean newborns have not been reported yet. Thus, this study aimed to understand variation in AF size and clinical implications of large AF sizes in newborns. This cohort study was conducted on nursery newborns born at a University Hospital between September 2019 and August 2020. AF size was measured at 24 to 48 hours after birth. Newborns with a large AF (> 3.6cm) were examined for other pathological reasons using radiological and laboratory tests. Demographic data were analyzed in relation to AF size. A total of 573 newborns were investigated. Their mean gestational age was 38.5 ± 1.2 weeks at birth and their mean birth weight was 3140 ± 450 g. Their mean AF size was 1.85 ± 0.83 cm (90 and 97-percentile of AF size were 2.96 and 3.65 cm, respectively). Among demographic factors, small for gestational age (SGA) weight, SGA head circumference, and multiple births were correlated with larger AF size. Among 18 infants with a large AF, 2 had intracranial abnormalities and 11 had vitamin D deficiency. This is the first recent study on AF sizes of Korean newborn infants. Their mean AF size was the smallest so far. For the largest AF size, a cutoff of 3.65 cm met the 97-percentile of the cohort. Both SGA weight and head circumference were risk factors for large AF size. For the largest AF size, intracranial lesions and vitamin D deficiency as well as SGA presented clinical implications.