Determination of Anterior Fontanelle Size among Apparently Healthy Term Newborns in North Central Nigeria.

Background: Anterior fontanelles (AFs) of healthy newborn infants vary widely in size, this being a function of race, geographical location, gender, birth weight, mode of delivery and gestation. Abnormal variations in AF size portend a serious pathology of the cranium or intracranial structures. The established reference value for normal AF size is, therefore, an essential diagnostic tool. This study was conducted to determine the mean AF size and factors that are associated with its variability among apparently healthy term neonates in Lokoja, North Central Nigeria.

Methods: AF size was measured in 200 healthy inborn term neonates between 24 and 48 h post-delivery using a modified version of Mattur's method. Other parameters measured were head circumference, birth weight and length. Relevant statistical methods were used for data analysis, and P < 0.05 at a confidence interval of 95% was considered statistically significant.

Results: Eighty-six (43%) of the babies were males, and the mean birth weight and gestation were 3.09 (0.37) kg and 38.8 (1.2) weeks, respectively. Majority (72%) were delivered spontaneously per vagina. The mean (± SD) AF size of the study neonates was 2.62 (0.72) cm (2.53 [0.61] cm in males and 2.69 [0.79] cm in females). Neither gender nor mode of delivery affected AF size significantly. There was no significant correlation between AF size and occipitofrontal circumference.

Conclusion: AF size for term babies in our hospital differs from AF sizes reported from other parts of the world, further reiterating the utility of local/regional neonatal AF reference values.