Estudo da prematuridade em fetos com hérnia diafragmática congênita: avaliação de fatores de predição

Abstract

Barbosa BML. Study on prematurity in fetuses with congenital diaphragmatic hernia (CDH): evaluation of predictive factors [Dissertation]. Sao Paulo: “Faculdade de Medicina, Universidade de Sao Paulo”; 2015. INTRODUCTION: Congenital diaphragmatic hernia (CDH) is a severe fetal malformation that leads to high mortality. Premature birth significantly increase the risk of neonatal morbidity and mortality in most diseases; but its relationship with congenital diaphragmatic hernia has not been well described. Fetuses with diaphragmatic hernia have a higher incidence of prematurity when compared to fetuses without malformations. Furthermore, prematurity is associated with worse post-natal survival in these fetuses. However, no studies have evaluated possible prenatal predictive factors. OBJECTIVES: To evaluate the incidence of prematurity in fetuses with congenital diaphragmatic hernia (CDH) and its possible predictive factors. METHODS: A retrospective cohort study was performed. Inclusion criteria were presence of congenital diaphragmatic hernia; absence of fetoscopy; absence of karyotype abnormality; maximum of one major malformation associated with diaphragmatic hernia; ultrasound monitoring at the Obstetrics Clinical of Clinicas Hospital at the University of Sao Paulo School of Medicine, from January 2001 to October 2014. The following variables were analyzed: maternal age, primiparity, associated maternal diseases, smoking, previous spontaneous preterm birth, fetal malformation associated with hernia, fetal hydrops, polyhydramnios during pregnancy, polyhydramnios on last ultrasound, fetal growth restriction, fetus large for gestational age, presence of intrathoracic liver, invasive procedures performed, side of hernia and observed to expected lung to head ratio (o/e LHR). On individual analysis, qualitative variables were assessed using the Chi-square test, and quantitative variables by the nonparametric test of Mann-Whitney. After individual analysis, a multiple logistic regression model with stewise variable selection method was performed to select variables variables that could influence the prediction of preterm delivery. A ROC curve was constructed with the significant variable, identifying the values with best sensitivity and specificity to be suggested for use in clinical practice. RESULTS: Eighty fetuses were evaluated, of which 21 (26.25%) were premature. After multiple analysis the o/e LHR was the only factor associated with prematurity (p = 0,02). The ROC curve showed that as the o/e LHR increases the sensitivity also increases and there is a decrease in the specificity of preterm delivery prediction, reaching a sensitivity rate of 93.3% and a specificity of 48.8% when o/e LHR is equal to 40%. The other variables were not associated with prematurity after multiple analysis. CONCLUSION: The incidence of prematurity was 26.25% in our population. The o/e LHR was the only predictor of prematurity in this sample. Descriptors: Obstetric labor, premature; Hernia diaphragmatic; Congenital Abnormalities; Forecasting; Risk assessment; Ultrasonics.