Zika vírus e gravidez: associação entre a infecção aguda na gravidez e a microcefalia do recém-nascido no estado do Rio de Janeiro

Abstract

The recent epidemic of Zika virus infection in Central and South America is one of the most serious global public health emergencies since the Ebola outbreak in West Africa. In Brazil, especially in the north, northeast, and southeast parts of the country, the ZIKV outbreak is a cause of concern for pregnant women and phpysicians because ZIKV intrauterine infection has been found to be associated with multiple brain malformations and microcephaly. The main objective of this study was to study the association between microcephaly and acute infection by Zika virus, during pregnancy, with laboratory confirmation. The secondary objectives were: to determine the risk of congenital infection correlated to the trimester of gestation in which the acute infection occurred, to compare the perinatal outcomes and know the sociodemographic profile of the Zika virus-infected women in pregnancy who had newborns with and without microcephaly. The study was observational with the cross-sectional type design. There were arrolled 1,609 pregnant women who had clinical symptoms of acute Zika virus infection during pregnancy, with a laboratory diagnosis confirmed by RT-PCR, in blood and /or urine specimens, collected in the years 2015 and 2016, and listed at the baseline Laboratory Management System (GAL) in the state of Rio de Janeiro. The gestational outcome was based on data collected from the Live Birth Information System (SINASC) and the Public Health Events Registry (RESP). Statistical modeling was used for the calculation of variables: the calculation of statistics and bivariate association measures. The proportions of the categorical variables were calculated in relation to two distinct groups: with and without microcephaly; and confidence intervals for the relative ratios with 95% confidence level. The trial was used to evaluate proportions, considering a significance level of 5%. The multivariate modeling was considered a logistic regression for the dichotomous variable and regression for the continuous variables. The statistical program used was R. 3.4.0 and Rstudio version 1.0.143. Of the 1,609 pregnant women studied, 316 (19.6%) were in the first trimester of pregnancy, 723 (44.9%) in the second trimester and 570 (35.5%) in the third trimester. The mean age was 26.5 years (± 6.9 years). As to race / color was found: 55% non-white and 45% white. In the spatial distribution of infected pregnant women, by region of the state: 87% occurred in the Metropolitan Region. Among the 1,609 pregnancies evaluated, 25 newborns presented microcephaly. Of the characteristics researched related to the occurrence of microcephaly, the variables "gestational age" at the time of infection and "birth weight" were statistically significant. Of the 25 microcephaly cases studied, 19 (76%) were associated with infection in the first trimester of pregnancy (p <0.001, OR = 13.7 95% (5.6-37.7)) and 48% microcephaly had birth weight <2,500 g (p <0.001, OR = 11.7 95% CI (5.2-26.2)). In the logistic regression, only the weight of the RN <2,500 g (OR = 12,54) and gestational age in the first trimester (OR = 14.05) were associated with the occurrence of microcephaly. These results can be used to guide health professionals in take conduct, as well as in the counseling of pregnant women living in epidemic areas.