From the Guidelines
Urinary tract infections (UTIs) are common in pregnant women due to physiological changes that occur during pregnancy, including hormonal changes, urinary tract relaxation, and increased bladder volume, which create an environment conducive to bacterial growth. These changes, as noted in the USPSTF reaffirmation recommendation statement 1, make pregnant women more susceptible to UTIs. The primary reasons include:
- Hormonal changes, particularly increased progesterone, causing relaxation of the smooth muscles in the urinary tract, which slows urine flow and allows bacteria more time to ascend the urinary tract
- The growing uterus putting pressure on the bladder, potentially causing incomplete emptying and urine stasis, creating an environment where bacteria can multiply
- Increased bladder volume and dilated ureters, further contributing to urine stagnation
- The urine itself becoming more conducive to bacterial growth during pregnancy due to increased glucose and hormone levels
As a result, pregnant women are about 20-40% more susceptible to UTIs compared to non-pregnant women. UTIs during pregnancy require prompt treatment, typically with pregnancy-safe antibiotics, as untreated infections can lead to serious complications including pyelonephritis, preterm labor, and low birth weight, as emphasized by the need for screening and treatment in the USPSTF statement 1. Preventive measures include staying well-hydrated, urinating frequently, practicing good hygiene, and emptying the bladder completely. The USPSTF recommends screening all pregnant women for asymptomatic bacteriuria at 12 to 16 weeks' gestation or at the first prenatal visit, if later, using urine culture as the preferred screening test 1.
From the Research
Prevalence of UTIs in Pregnant Women
- Urinary tract infections (UTIs) are the most common type of infection during pregnancy, affecting up to 10% of pregnant women 2.
- The global prevalence of UTI in pregnant women was found to be 37.7% in a study conducted from 2021 to 2022 3.
- UTIs are also recognized as the second most common ailment of pregnancy, after anemia 2.
Risk Factors for UTIs in Pregnant Women
- A history of UTI prior to pregnancy is a significant risk factor for developing UTI during pregnancy, with an odds ratio (OR) of 4.05 3.
- Diabetes mellitus is also a risk factor, with an OR of 2.25 3.
- Overweight pregnant women are at a higher risk of developing UTI, with an OR of 1.48 3.
- The third trimester of pregnancy is a protective factor for UTI, with an OR of 0.65 3.
Complications of UTIs in Pregnant Women
- Untreated asymptomatic bacteriuria can lead to acute pyelonephritis in up to 30% of mothers, increasing the risk of maternal and neonatal complications such as preeclampsia, preterm birth, intrauterine growth restriction, and low birth weight 4.
- UTIs have been associated with adverse pregnancy outcomes, including increased rates of preterm delivery and low birth weight 5.