Etiological factors of preterm birth and consequences of perinatal factors in child health: birth cohorts in two Brazilian cities (BRISA project)

Abstract

The present study consists of two major subprojects. The first will evaluate new risk factors for preterm birth, such as components of two causality chains, i.e., the neuroendocrine and immune-inflammatory hypotheses. According to the first hypothesis, stress during pregnancy may favor the release of corticotrophin releasing factor (CRH) and the induction of preterm delivery potentiated by CRH gene polymorphisms. According to the second hypothesis, maternal infections may be potentiated by genetic susceptibility, promoting the liberation of inflammatory mediators leading to preterm birth. These hypotheses will be tested in a case-control study within a cohort started during the 5th month of prenatal care in a convenience sample covering 3.000 births in two cities, São Luís (MA) and Ribeirão Preto (SP). This cohort will be re-interviewed at birth and during the 1st year of life. The second subproject will evaluate indicators of perinatal health and their reflexes on preterm and low birth weight rates, comparing them to data for cohorts studied over the last thirty years in the two municipalities. We will also evaluate the impact of preterm birth and other birth conditions on growth, development of insulin resistance, neurological and behavioral alterations, risk factors for allergy and wheezing, and changes in oral health. This evaluation will be performed by interviewing the mothers, by anthropometric evaluation and blood collection for biochemical evaluation and by genetic studies of the children, by the application of allergy skin test and by dental evaluation. This cohort will be started at birth, covering a representative sample of 6000 births in São Luís and 7.500 births in Ribeirão Preto and will be re-evaluated during the first year of Iife. (AU)