RESUMEN
OBJECTIVES: Short cervical length is a predictor of preterm birth. We evaluated if there were racial differences in variables associated with cervical length in pregnant Brazilian women. METHODS: Cervical length was determined by vaginal ultrasound in 414 women at 21 weeks gestation. All women were seen at the same clinic and analyzed by the same investigators. Women found to have a short cervix (≤25 mm) received vaginal progesterone throughout gestation. Composition of the vaginal microbiome was determined by analysis of the V1-V3 region of the gene coding for bacterial 16S ribosomal RNA. Demographic, clinical and outcome variables were determined by chart review. Subjects were 53.4% White, 37.2% mixed race and 9.4% Black. RESULTS: Pregnancy, medical history and education level were similar in all groups. Mean cervical length was shorter in Black women (28.4 mm) than in White (32.4 mm) or mixed race (32.8 mm) women (p≤0.016) as was the percentage of women with a short cervix (23.1, 12.2, 7.8% in Black, White, mixed race respectively) (p≤0.026). Mean cervical length increased with maternal age in White (p=0.001) and mixed race (p=0.045) women but not Black women. There were no differences in bacterial dominance in the vaginal microbiota between groups. Most women with a short cervix delivered at term. CONCLUSIONS: We conclude that Black women in Brazil have a shorter cervical length than White or mixed race women independent of maternal age, pregnancy and demographic history or composition of the vaginal microbiome.