Deficiência de vitamina D: fator de risco para parto prematuro em adolescentes.

Abstract

Low serum 25-hydroxyvitamin D concentrations during pregnancy have been associated with adverse pregnancy outcomes such as premature birth. Objectives: To evaluate the association of maternal serum 25-hydroxyvitamin D status with premature birth in adolescence. Design: Study cohort restricted population. The outcome analyzed was premature birth, defined by being what occurs before 37 weeks of gestation. The study period was from February 2012 to January 2014. 615 adolescents with singleton pregnancies who were attending first-trimester screening in Campina Grande, Paraíba- Brazil were sampled. Serum 25-hydroxyvitamin D levels were measured. Outcomes of the delivery and newborn were collected. A standardized questionnaire about socioeconomic, clinical and laboratory variables of pregnancy and childbirth was applied. Serum levels of 25-hydroxyvitamin were considered below 20 ng/mL as deficiency and between 20 and 29 ng/mL as insufficiency. All women were followed by a single obstetrician. Multivariate logistic regression was conducted to analyze the association between low 25-hydroxyvitamin D concentrations and preterm birth. Results: The prevalence of preterm birth delivery in adolescents was 23% and vitamin D deficiency was observed in 59% of the cohort. With a 25-hydroxyvitamin D concentration less than 20 ng/mL, the odds ratios were 3.31 for premature birth (95% confidence interval, 1.52-7.19; P<.002). A 25-hydroxyvitamin D concentration <20 ng/mL had 80% sensitivity and 45% specificity for premature birth. The cutoffs with the best combination of sensitivity and specificity were 14 ng/mL for premature birth (66.7% sensitivity and 71.0% specificity). The addition of 25-hydroxyvitamin D deficiency to maternal and clinical risk factors improve the ability to predict premature birth in 8%. Conclusion: Low 25-hydroxyvitamin D levels are associated with preterm birth in adolescents.