Associations between bacterial infections and blood pressure in pregnancy

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

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.

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.

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.

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