Maternal Group B Streptococcus Infection Correlates Inversely With Preeclampsia in Pregnant African American Women

To determine whether an association exists between group B Streptococcus (GBS) colonization and preeclampsia among pregnant Black women.

This retrospective cross-sectional study involved Black women who gave birth at State University of New York Downstate Hospital between January 2010 and December 2017. Data were collected from the Obstetric Department, including delivery date, time, mode of delivery, age of the mother, weeks of gestation at delivery, and antepartum complications. The GBS test results were originally determined using the eSwab transport system. Preeclampsia was defined based on the American College of Obstetricians and Gynecologists criteria for the periods 2010-2012 and 2013-2017. The primary outcome was whether GBS was associated with the outcome of preeclampsia in the population of Black women. Covariates, including smoking status, gestational age, parity, body mass index, maternal age, and presence of herpes simplex virus (HSV) and human immunodeficiency virus (HIV) were examined as potential confounders. Chi-squared test and logistic regression model were used, presenting odds ratios with 95% confidence intervals (P < 0.050), analyzed with SAS on Demand for Academics (SAS Institute, Inc., NY).

Among the 8,019 Black women included in this study, GBS-positive women (n = 977) had a 53% reduction in the likelihood of being diagnosed with preeclampsia compared to GBS-negative women (adjusted odds ratio, 0.47; 95% confidence interval, 0.32-0.70). We did not find evidence of differences in the distribution of smoking habits (P = 0.783) or maternal age (P = 0.107) between GBS-positive and GBS-negative women. However, the GBS-positive women tended to be less likely to have a preterm delivery (9.62% (94/977) vs. 24.24% (1707/7042), P < 0.001), less likely to be nulliparous (33.37% (326/977) vs. 37.87% (2667/7042), P = 0.006), and less likely to be obese (51.38% (502/977) vs. 55.30% (3894/7042), P < 0.001) compared with GBS-negative women. In contrast, GBS-positive women were more likely to have a comorbid infection than their counterparts: HSV (5.94% (58/977) vs. 2.63% (185/7042), P < 0.001) and HIV (1.54% (15/977) vs. 0.82% (58/7042), P = 0.028).

We found a reduced likelihood of preeclampsia among women who were positive for GBS at delivery. Given the cross-sectional nature of our study, more research is needed to further explore this association.