Background: Pregnancy causes physiologic changes that increase risk of urinary tract infection (UTI), including acute cystitis and asymptomatic bacteriuria. US clinical practice guidelines recommend universal UTI screening during pregnancy, as they can cause serious maternal and neonatal harms. A few US studies suggest that incidence may be highest in Hispanic, American Indian or Alaska Native, and Black populations but did not use contemporary data and ascertained UTI from interviews after delivery.
Objectives: To characterize the incidence of UTI during pregnancy, overall and by racial and ethnic groups.
Methods: We used electronic health record (EHR) data from Kaiser Permanente Washington (KPWA)—an integrated health system in the US—to identify pregnancies in enrolled individuals aged 15–49 from 2010–2022. UTI was identified with diagnostic codes. We restricted analyses to the 1st UTI per pregnancy but allowed individuals to contribute >1 pregnancy. We calculated UTI incidence and 95% confidence intervals (CIs), overall and by racial and ethnic groups. We used race and ethnicity from the EHR; if a person identified as >1 race or ethnicity, their pregnancy was counted in multiple groups, except for non-Hispanic white, which represented white race only. We also calculated age-standardized incidence in each racial and ethnic group, standardized to the overall population’s age distribution.
Results: There were 43,973 eligible pregnancies: 75.3% livebirths, 23.9% miscarriages or terminations, and <1% stillbirths. We had the following racial and ethnic distribution: 2.1% American Indian or Alaska Native, 2.6% in Native Hawaiian or Pacific Islander, 8.6% Hispanic, 9.6% Black, 16.6% Asian, and 60.5% non-Hispanic white. The median age was 31 years (interquartile range: 27–34). Overall, 10.8% of pregnancies (95% CI: 10.5–11.0%) were coded with a UTI. Incidence was highest in American Indian or Alaska Native individuals (16.2%, 13.9–18.6%), followed by Native Hawaiian or Pacific Islander (15.2%, 13.1–17.3%), Hispanic (14.4%, 13.3–15.5%), Black (12.4%, 11.4 –13.4%), non-Hispanic white (10.1%, 9.7–10.4%), and Asian individuals (9.8%, 9.1–10.4%). Age-standardized results were similar, with considerable differences remaining between groups. Incidence was lower after limiting to UTIs with an antibiotic dispensing, but patterns by race and ethnicity held.
Conclusions: In this US integrated health system population, UTI was common in pregnancy, with considerable differences in incidence between racial and ethnic groups. As UTI in pregnancy is associated with increased risk of adverse pregnancy outcomes, it is critical to treat these infections appropriately to avoid differential infection incidence translating to inequities in adverse pregnancy outcomes.
