Racial disparities in cervical length for prediction of preterm birth in a low risk population.

PURPOSE: Racial minorities experience higher rates of spontaneous preterm birth (sPTB). Our objective was to evaluate whether there are racial discrepancies in the incidence of second trimester short cervical length (≤25 mm).

MATERIALS AND METHODS: Retrospective cohort of women with singleton gestations without prior sPTB undergoing universal second trimester transvaginal ultrasound cervical length (CL) screening between January 2012 and December 2013. Black women were compared to non-Hispanic white women. Our primary outcome was the incidence of CL ≤25 mm. Secondary outcomes were incidence of PTB ≤37 weeks, delivery mode, birth weight and neonatal intensive care unit (NICU) admission.

RESULTS: Black women (n = 1092) differed from non-Hispanic white women (n = 659) with respect to maternal age (26.0 versus 30.7 years), gravidity (3.1 versus 2.1), prepregnancy BMI (29.6 versus 25.0 kg/m2 ), and smoking status (9.8% versus 16%), respectively (p < 0.001). Black women had higher incidence of CL ≤25 mm (1.9% versus 0.6%; OR: 3.21 [1.1-9.4]), rates of sPTB (8.5% versus 4.4%; aOR: 1.95 [1.1-3.4]), incidence of low birthweight infants (<2500 g, 8.3% versus 5.6%; aOR 1.80 [1.1-3.0]) and were more likely to have their infants admitted to the NICU (16% versus 11%; OR: 1.52 [1.0-2.3]).

CONCLUSIONS: Black women had a 2.8-fold increased risk of CL ≤25 mm compared non-Hispanic white women in a low-risk population.