Microcephaly: normality parameters and its determinants in northeastern Brazil : a multicentre prospective cohort study

Abstract

Brazil was marked by a serious epidemic of microcephaly due to still obscure causes. According to the Ministry of Health, the number of suspected cases of microcephaly reached 2401. However, there is controversy in Brazil regarding the most appropriate cut-off point and diagnosis criteria. The present study aimed to measure the prevalence of microcephaly and identify its determinants, in a prospective cohort from a multicentre hospital-based study. The sample comprised 3623 live births admitted to the NICU, the dependent variable being cephalic perimeter. Bootstrap and logistic regression models were used to analyse data. 32 cm corresponded to tenth percentile in this population, with a confidence interval between 31.82 and 32.18. Intrauterine growth restriction, pregnancies resulting in congenital anomalies, oligohydramnios and the maternal use of steroids were associated with microcephaly. This work raises discussion on the cut-off point used for the diagnosis of microcephaly at a population level in a country with an outbreak as well as factors that can be associated with the outcome presented.