O23.13 Infections of bladder in pregnancy, third trimester

Name of the Condition

• Infections of bladder in pregnancy, third trimester
• ICD-10 Code: O23.13

Summary

Infections of the bladder during the third trimester of pregnancy, commonly referred to as cystitis, involve bacterial inflammation of the bladder lining. These infections are a frequent complication of pregnancy due to physiological changes that increase susceptibility to urinary tract infections (UTIs). Prompt diagnosis and treatment are essential to prevent progression to more severe infections, such as pyelonephritis, and to reduce risks to both the mother and fetus.

Causes

Bladder infections in the third trimester are typically caused by ascending bacterial infection, most commonly Escherichia coli. Hormonal changes, such as increased progesterone levels, and anatomical shifts from the growing uterus can reduce urinary flow and promote bacterial growth. Reduced bladder emptying and altered vaginal flora may also contribute to infection development.

Risk Factors

• Previous history of UTIs or bladder infections.
• Asymptomatic bacteriuria during pregnancy.
• Sexual activity, which may introduce bacteria into the urethra.
• Poor hydration or inadequate bladder emptying.
• Underlying conditions like diabetes or immunosuppression.

Symptoms

• Burning or pain during urination (dysuria).
• Frequent or urgent urination (frequency/urgency).
• Lower abdominal or pelvic discomfort.
• Cloudy, foul-smelling urine.
• Blood in the urine (hematuria).

Diagnosis

Diagnosis typically involves urinalysis to detect bacteria or abnormal cells, urine culture to identify pathogens, and possibly a urine dipstick test for nitrites or leukocyte esterase. In some cases, additional tests like a urine PCR or imaging may be used to rule out complications.

Treatment Options

Treatment usually includes a course of antibiotics safe for pregnancy, such as nitrofurantoin or cephalexin, tailored to the specific pathogen. Adequate hydration and pain management may also be recommended. Severe cases may require hospitalization for intravenous antibiotics.

Prognosis and Follow-Up

With prompt treatment, most bladder infections in the third trimester resolve without long-term complications. Follow-up may include repeat urine cultures to ensure eradication of infection and monitoring for recurrence, especially as pregnancy progresses.

Complications

Untreated infections can progress to pyelonephritis, which may increase the risk of preterm labor, low birth weight, or maternal sepsis. Rarely, severe infections can lead to kidney damage or systemic infection.

Lifestyle & Prevention

• Maintain good hydration to flush bacteria from the urinary tract.
• Urinate promptly when needed to avoid bladder stasis.
• Practice proper hygiene, including wiping front to back.
• Consider cranberry products or probiotics, though evidence is limited.
• Avoid irritants like harsh soaps or bubble baths.

When to Seek Professional Help

Seek care if symptoms worsen, persist after treatment, or if fever, chills, or flank pain develop, as these may indicate a more serious infection like pyelonephritis.

Tips for Medical Coders

Document the trimester (third trimester) and confirm the infection is localized to the bladder. Ensure the diagnosis aligns with clinical findings and treatment. Code O23.13 is specific to bladder infections in the third trimester; avoid using it for infections in other trimesters or genitourinary sites.