448: Is cervical length similarly predictive of preterm birth across races in twin gestation?

Abstract

Listen

Translate article

There is evidence of racial variation in transvaginal cervical length (TVCL) as well as spontaneous preterm birth (SPTB) in singleton pregnancies. We sought to determine whether racial differences in TVCL are present in women with twin gestations and whether TVCL has similar predictive value for SPTB across races. This is a retrospective study of twin gestations at a tertiary care center that delivered between 2008 and 2015. All pregnancies were included except those with spontaneous or iatrogenic pregnancy reduction, lethal fetal anomaly and mono-amniotic placentation. The primary outcome of interest was gestational age at delivery (GAD). Univariate analysis was performed to compare baseline demographic and pregnancy characteristics across Black, White, Asian, Hispanic and Other/unknown races. The shortest (minimum) TVCL (mTVCL) between 18 and 24 weeks was calculated for each patient and the distributions of mTVCL and GAD were compared between races by ANOVA. To determine the relative contribution of race and mTVCL to GAD, a linear regression model was fit for patients that delivered spontaneously with GAD as the dependent variable. Interaction variables were used to determine whether mTVCL contributed to GAD similarly for different races. We identified 1,289 women that met inclusion criteria. Black women were more likely to be multiparous and have a history of preterm delivery. They were less likely to have monochorionic placentation or history of a LEEP. (Table 1) Black women had a mean mTVCL of 3.23 cm, which was significantly shorter than any other race. Differences in mTVCL between all other races were not statistically significant. In the linear regression model, each 1 cm decrease in mTVCL was associated with a baseline 0.90 week (p < 0.001) reduction in GAD for all races. For black women, each 1 cm decrease in mTVCL was associated with an additional 2.48 week decrease in GAD beyond the 0.90 week baseline (Table 2). Black women with twin gestation have significantly shorter cervices than women of all other races and each unit decrease in TVCL is associated with earlier GAD in black women compared to women of other races.View Large Image Figure ViewerDownload Hi-res image Download (PPT)