RESUMO
AIM: To evaluate the effect of intrauterine growth restriction (IUGR) on the success rate of labor induction of preterm pregnancies complicated by hypertensive disorders. METHODS: A retrospective cohort study conducted using data from the Centers for Disease Control and Prevention's Linked Birth-Infant Death File in the United States from 2009 to 2013. Our cohort included live normal singleton cephalic pregnancies complicated by hypertensive disorders that underwent induction of labor and delivered between 24 and 35.6 weeks' gestation. Study subjects were categorized by the presence or absence of IUGR. Multivariate logistic regression was used to estimate the adjusted effect of IUGR on risk of caesarean deliveries. RESULTS: Of 41 640 births meeting study criteria, 39 890 had no IUGR and 1750 had IUGR infants. The overall caesarean delivery rate was 22.2%, with caesarean delivery risk being higher among pregnancies complicated by IUGR versus those not complicated by IUGR (33.2% vs 21.7%, respectively) (odds ratio 2.00, 95% confidence interval 1.78-2.25). The effect of IUGR on risk of caesarean sections was most pronounced for gestational ages between 28 and 36 weeks. The effect of IUGR was highest among obese women, with the risk of caesarean in IUGR vs non-IUGR pregnancies being 62.8% vs 41.4%, respectively (odds ratio 2.53, 95% confidence interval 1.98-3.24). CONCLUSION: Induction of labor of preterm pregnancy complicated by hypertensive disorders should be considered a reasonable option for delivery; however, in the context of IUGR, women should be informed of the considerable higher risk of caesarean delivery.
