We estimated risk factors associated with suspected neuropsychomotor developmental delay at age 2 years, in a birth cohort in the Brazilian Amazon. The Maternal and Child Health and Nutrition in Acre (MINA-Brasil) study is a population-based birth cohort involving children born between July 2015 and June 2016 in the municipality of Cruzeiro do Sul, in the Brazilian state of Acre. We assessed neuropsychomotor development in 735 and 819 children at one and 2 years of age, respectively, using the Denver II screening test. Multivariate Poisson regression models were used to investigate the factors associated withsuspected developmental delay at age 2 years. The frequency of suspected developmental delay was 29.5 and 51.0% at one and 2 years of age, respectively, with a cumulative incidence of 41.6% and a persistence of 60.6% between the first and second years of life. After adjustment, the risk of developmental delay at 2 years of age was found to be higher for children born to women with fewer years of education and whose mothers had urinary tract infection during pregnancy. Other risk factors included male sex, low height for age at 2 years, malaria at childhood, pacifier use and limited child stimulation at age 2 years.

OBJECTIVE: To review observational studies on the association between breastfeeding (BF) practices and head circumference (HC) of children < 2 years old. METHODS: A systematic review was conducted using the following electronic databases of ​​health sciences: PubMed, Latin American and Caribbean Literature in Health Sciences (Lilacs), Web of Science and Scopus. We selected observational studies published in any language from January 01, 2010 to November 19, 2021, from different populations that investigated the association between BF practice and HC among healthy children <2 years old. Titles and abstracts were screened independently by two evaluators. RESULTS: From the 4229 articles identified, 24 were included in this review: 6 cross-sectional, 17 longitudinal, and 1 case-control. The studies varied in their definition of the variables for BF and in reporting its practice, frequency, duration, and feeding method. Regarding HC, the authors analyzed the mean differences, abnormal values ​​(z-score above + 2SD or below -2SD according to the World Health Organization (WHO) growth standards, 2007), and longitudinal growth parameters. The findings of this review suggest that BF may have a positive relationship with HC at the beginning of life. CONCLUSIONS: Our findings suggest that BF, especially exclusive BF, may play a protective role against abnormal HC values in young children. However, more robust evidence with standardized BF indicators and WHO growth standards (2007) are required.