Idade Materna, Desfechos Perinatais Adversos e Gravidez na Adolescência. Resultados da Coorte BRISA.

Abstract

The importance of maternal age on perinatal outcomes has been subject of several studies over the years. Teenage pregnancy and pregnancy after the age of 35 has been associated with adverse perinatal outcomes. Pregnancies that occur at the extremes of reproductive life deserve special attention. Objectives – To verify the association between different maternal ages and perinatal outcomes: preterm birth and intrauterine growth restriction and to verify the changing of characteristics which can influence the proportion of teenage pregnants in the city of São Luís – Maranhão - Brazil. Methodology – Comparative study of two birth cohorts held in the city of São Luís - MA, the first one in 1997 and second one in 2010, where pregnancy and birth characteristics were studied. Frequency and 95% confidence interval were used for description. Multiple logistic regression model was used to asses adjusted oddsratio of maternal age associated to outcomes: preterm birth and intrauterine growth restriction. Variations between cohorts were evaluated using chi-square test. A p-value <0.05 was considered statistically significant. Results - Multivariate analysis showed a statistically significant increase in the prevalence of preterm birth in early teenage mothers (OR=1.65 p=0.044) compared to those aged 20-35 years. Also an increased prevalence of preterm birth was observed among late teenage mothers (OR=1.33 p=0.013). Among those with advanced maternal age (over 35 years), despite the increase in the prevalence of preterm birth, there was borderline statistical significance (OR=1.39) (p=0.055). There was no association between maternal age and the increased prevalence of intrauterine growth restriction. There was a decrease in the percentage of adolescent mothers, from 29.4% in 1997 to 18.7% in 2010. This decrease occurred both in the age group 12-15 years, fell from 3.6% to 2, 2%, as in the range of 16 to 19, from 25.8% to 16.4%. Proportion of teenage mothers with adequate schooling to age had a significant increase from 14.0% in 1997 to 42.3% in 2010 (p<0.001). This increase was observed both among early and late adolescents. Conclusion – Prevalence of preterm birth was higher among early and late teenage mothers. Maternal age was not an independent associated factor for intrauterine growth restriction. From 1997 till 2010 there was a decrease in the percentage of teenage pregnants and an increase in the proportion of teenagers with adequate schooling to age.