Full-term newborns with congenital microcephaly and macrocephaly in Southwest Nigeria.

This retrospective cohort study set out to determine perinatal and maternal factors associated with full-term (≥37 weeks) newborns with abnormal head sizes at birth in Lagos, Nigeria. Age and gender specific head circumference was determined with the current Child Growth Standards of the World Health Organization while maternal and infant factors independently associated with microcephaly (z-score < -2) and macrocephaly (z-score >2) were explored using multinomial logistic regression. Of the 3196 infants enrolled, 340 (10.6%) were microcephalic underpinned by suspected cytomegalovirus (CMV) infection while 74 (2.3%) were macrocephalic. Compared with normocephalic newborns, microcephalic infants were more likely to be growth restricted in-utero (OR: 10.89; 95% CI: 7.86-15.08); underweight (OR: 18.61; 95% CI: 13.28-26.07); stunted (OR: 15.45; 95% CI: 11.70-20.40); and wasted (OR: 3.64; 95% CI: 2.52-5.27); as well as having an increased risk of unconjugated hyperbilirubinaemia but unlikely to be associated with prolonged/obstructed labour (OR: 0.49; 95% CI: 0.31-0.78). In contrast, macrocephalic infants were likely to be delivered by emergency caesarean section (OR: 2.32; 95% CI: 1.33-4.04) and at greater risk of neonatal sepsis (OR: 4.12; 95% CI: 1.68-10.40). Risk of sepsis in macrocephalic infants was more than two-fold compared with microcephalic infants but not statistically significant (p = 0.066). In conclusion, improved fetal growth monitoring, early nutritional intervention and management of perinatal infections are likely to curtail the burden of congenital microcephaly and macrocephaly in resource-poor settings. The underpinnings of unconjugated hyperbilirubinaemia in microcephalic infants in this CMV hyper-endemic population merit further investigation.