A urinary tract infection (UTI) occurs when bacteria invade and multiply within the urinary system, most commonly affecting the bladder and urethra. A miscarriage is the unexpected loss of a pregnancy before 20 weeks of gestation. This article explores the relationship between UTIs and miscarriage, particularly during the first trimester.
Understanding Urinary Tract Infections During Pregnancy
Pregnant individuals experience physiological changes that increase their susceptibility to urinary tract infections. Hormonal shifts can relax smooth muscles in the urinary tract, and the growing uterus places pressure on the bladder and ureters, potentially leading to urinary stasis where urine can pool. These changes create an environment conducive to bacterial growth. Additionally, urine composition changes, becoming less acidic and containing more sugars and proteins, further promoting bacterial proliferation.
Urinary tract infections in pregnancy can manifest in different forms. Asymptomatic bacteriuria (ASB) involves bacteria in the urine without symptoms, affecting about 1 in 10 pregnant women. Cystitis is a bladder infection with symptoms, while pyelonephritis signifies a more serious kidney infection. The most frequent bacterium responsible for UTIs during pregnancy is Escherichia coli (E. coli), though other bacteria can also cause these infections.
How UTIs Can Affect Pregnancy Outcomes
A simple urinary tract infection, especially when promptly identified and treated, is not a direct cause of miscarriage. Most miscarriages, particularly in the first trimester, are due to chromosomal abnormalities. However, untreated or severe UTIs can lead to complications that might increase risks for both the pregnant individual and the developing fetus.
If a lower urinary tract infection remains untreated, bacteria can ascend from the bladder to the kidneys, resulting in pyelonephritis. This serious kidney infection can cause high fever, chills, back pain, and lead to systemic complications like maternal sepsis. While rare, severe systemic infections and inflammation from untreated pyelonephritis have been associated with risks such as preterm labor and low birth weight. The mechanism involves inflammation and bacterial toxins potentially affecting uterine contractions or fetal well-being, though miscarriage directly caused by a UTI in the first trimester is uncommon.
Recognizing and Treating UTIs in Pregnancy
Recognizing UTI symptoms and seeking timely medical attention is important during pregnancy. Common signs include:
Painful or burning sensations during urination.
Increased frequency or urgency to urinate.
Cloudy or strong-smelling urine.
Pelvic pain or discomfort.
If the infection has spread to the kidneys, symptoms can become more severe, including fever, chills, nausea, vomiting, and back pain.
Medical professionals diagnose UTIs through urine tests. A urinalysis checks for white blood cells, red blood cells, and bacteria, while a urine culture identifies the specific type of bacteria. Treatment for UTIs during pregnancy primarily involves antibiotics safe for both the pregnant individual and the fetus, such as amoxicillin, cephalexin, or nitrofurantoin. Complete the entire course of antibiotics, even if symptoms improve, to ensure the infection is fully eradicated and prevent recurrence. Self-diagnosis or self-treatment should be avoided.
Preventing UTIs During Pregnancy
Certain practices can help reduce the likelihood of developing urinary tract infections during pregnancy. Drinking plenty of fluids, especially water, helps to dilute urine and flush bacteria. Urinating frequently and emptying the bladder completely prevents bacteria from multiplying. It is helpful to urinate both before and after sexual activity.
Proper hygiene practices are also beneficial. Always wipe from front to back after using the toilet to prevent bacteria from entering the urethra. Wearing breathable cotton underwear and avoiding tight-fitting clothing can help maintain a dry environment. Regular prenatal check-ups are important, as healthcare providers routinely screen for asymptomatic bacteriuria during early pregnancy, allowing for early detection and treatment even without symptoms.