Associations between bacterial infections and blood pressure in pregnancy

Abstract

Objectives: To test the hypothesis that bacterial infections in pregnancy are related to maternal blood pressure.

Study design: Bacterial infection was assessed using antibiotic usage as a surrogate and its association with blood pressure in pregnancy tested in the Cambridge Baby Growth Study.

Main outcome measures: Antibiotic usage in pregnancy was self-reported in questionnaires. Blood pressure measurements at four time points in pregnancy were collected from the hospital notes of 622 women.

Results: Using all the available blood pressure readings (adjusted for weeks gestation) antibiotic usage was associated with a higher mean arterial blood pressure across pregnancy: antibiotics used 85(84, 87)mmHg vs. no antibiotics used 83 (83, 84) mmHg (β=2.3 (0.6, 4.0) mmHg, p=9.6×10^-3, from 621 individuals). Further analysis revealed that antibiotic usage was associated with diastolic (β=2.3 (0.6, 4.0) mmHg; p=7.0×10^-3) more than systolic blood pressure (β=1.4(-0.9, 3.7)mmHg; p=0.2). The effect size associated with antibiotic usage appeared to rise slightly after the first trimester.

Conclusions: Bacterial infection in pregnancy, as assessed by self-reported antibiotic usage, is associated with small rises in blood pressure.

Keywords: Antibiotics; Gestational hypertension; Pre-eclampsia; Pregnancy.