Complicated cystitis in pregnancy

Complicated cystitis in pregnancy refers to a lower urinary tract infection occurring in a pregnant woman where physiological changes of pregnancy, maternal factors, or urinary tract abnormalities increase the risk of treatment failure, recurrence, or progression to more severe infection.

Pregnancy predisposes women to urinary tract infections (UTIs) due to hormonal and anatomical changes, including ureteric dilatation, reduced ureteric peristalsis, and compression of the urinary tract by the enlarging uterus. These changes promote urinary stasis and increase the risk of bacterial multiplication and ascending infection.

Complicated cystitis requires prompt diagnosis and appropriate antimicrobial treatment because untreated infection may progress to acute pyelonephritis, which is associated with maternal complications such as sepsis and adverse pregnancy outcomes, including preterm delivery and low birth weight.

Epidemiology

Urinary tract infections are among the most common bacterial infections during pregnancy. Pregnant women are at increased risk due to physiological changes affecting the urinary system.

The most common causative organisms are similar to those causing UTIs in the general population, including:

• Escherichia coli (most common pathogen)

• Klebsiella pneumoniae

• Proteus species

• Staphylococcus aureus

Complicated cystitis occurs more frequently in women with additional risk factors such as diabetes mellitus, structural abnormalities of the urinary tract, recurrent UTIs, or urinary tract instrumentation.

Risk factors

Risk factors for complicated cystitis in pregnancy include:

• Pregnancy-related urinary tract changes

• Previous urinary tract infection

• Recurrent UTI

• Diabetes mellitus

• Structural abnormalities of the urinary tract

• Renal stones

• Vesicoureteric reflux

• Urinary tract obstruction

• Immunosuppression

• Previous urinary tract instrumentation

• Poor bladder emptying

Pathophysiology

During pregnancy, increased progesterone levels cause relaxation of urinary tract smooth muscle, resulting in reduced ureteric peristalsis and urinary stasis. The enlarging uterus may compress the ureters, particularly on the right side, contributing to urinary tract dilatation.

Urinary stasis allows bacteria to multiply and ascend from the lower urinary tract. Bacterial colonization of the bladder mucosa causes inflammation, leading to symptoms of cystitis.

If untreated, infection may ascend through the ureters to involve the kidneys, resulting in acute pyelonephritis and potentially systemic infection.

Clinical presentation

Complicated cystitis in pregnancy may present with typical lower urinary tract symptoms, although symptoms may be less pronounced in some pregnant women.

Symptoms

Common symptoms include:

• Dysuria (painful urination)

• Increased urinary frequency

• Urinary urgency

• Suprapubic discomfort or pain

• Lower abdominal discomfort

• Haematuria (occasionally)

Symptoms suggestive of progression to upper urinary tract infection include:

• Fever

• Flank pain

• Chills

• Nausea and vomiting

Clinical signs

Possible clinical findings include:

• Suprapubic tenderness

• Fever in cases of systemic involvement

• Costovertebral angle tenderness suggesting pyelonephritis

• Signs of sepsis in severe infection

Diagnostic criteria

Diagnosis of complicated cystitis in pregnancy is based on:

• Presence of urinary symptoms compatible with cystitis.

• Evidence of urinary infection on laboratory testing.

Diagnostic support includes:

• Pyuria or positive leukocyte esterase on urinalysis.

• Positive urine culture with significant bacterial growth.

• Identification of causative organism and antimicrobial sensitivity where available.

Investigations

Urinalysis

Urinalysis may show:

• Increased white blood cells (pyuria)

• Positive leukocyte esterase

• Positive nitrites

• Microscopic haematuria

Urine microscopy

May demonstrate:

• Increased white blood cells

• Bacteria

• Urinary sediments suggestive of infection

Urine culture and antimicrobial sensitivity testing

Urine culture is recommended in complicated cystitis to:

• Confirm bacterial infection.

• Identify causative organisms.

• Guide appropriate antibiotic selection.

Additional investigations where indicated

Depending on clinical severity or recurrent infection:

• Full blood count

• Serum creatinine

• Kidney, ureter, and bladder ultrasound to assess structural abnormalities, stones, or obstruction

Management

Management aims to:

1. Eradicate bacterial infection.

2. Prevent progression to pyelonephritis.

3. Reduce maternal and fetal complications.

4. Identify and manage underlying risk factors.

Treatment includes:

• Appropriate antimicrobial therapy safe for pregnancy.

• Adequate hydration.

• Clinical monitoring for treatment response.

Non-pharmacological treatment

Non-pharmacological measures include:

• Ensure adequate fluid intake unless contraindicated.

• Encourage regular bladder emptying.

• Avoid delaying urination when there is an urge to void.

• Maintain good perineal hygiene.

• Identify and manage contributing factors such as urinary obstruction or stones.

Patients should be advised to seek medical attention if symptoms worsen or if features suggestive of upper urinary tract infection develop.

Pharmacological treatment

Antibiotic therapy

Recommended treatment options for complicated cystitis in pregnancy include:

• Nitrofurantoin (PO) 100 mg every 12 hours for 5 days.

OR

• Amoxicillin + clavulanic acid (FDC) (PO) 625 mg every 12 hours for 7 days.

Antibiotic selection should be guided by urine culture and antimicrobial sensitivity results where available, particularly in recurrent or complicated infections.

Management according to underlying cause

Recurrent urinary tract infection

Management includes:

• Confirming bacterial sensitivity.

• Identifying predisposing factors.

• Considering specialist evaluation where recurrent infections persist.

Urinary tract abnormalities

Patients with structural abnormalities, urinary obstruction, or stones require evaluation and management of the underlying condition.

Diabetes mellitus

Management includes:

• Optimizing blood glucose control.

• Close monitoring because of increased risk of severe infection.

Referral

Refer pregnant women urgently if they have:

• Features suggestive of acute pyelonephritis:

  • Fever

  • Flank pain

  • Vomiting

  • Costovertebral angle tenderness

• Features of urosepsis:

  • Hypotension

  • Tachycardia

  • Confusion

  • Evidence of organ dysfunction

• Failure to improve with appropriate antibiotic therapy.

• Recurrent complicated urinary tract infections.

• Known structural urinary tract abnormalities.

Complications

Maternal complications include:

• Acute pyelonephritis

• Urosepsis

• Acute kidney injury

• Recurrent urinary tract infection

Pregnancy-related complications include:

• Preterm labour

• Low birth weight

• Premature rupture of membranes

• Fetal complications associated with severe maternal infection

Prognosis

With early diagnosis and appropriate antibiotic treatment, most cases of complicated cystitis in pregnancy resolve without complications.

Delayed treatment or inadequate therapy increases the risk of ascending infection, pyelonephritis, sepsis, and adverse pregnancy outcomes.

Prevention

Preventive measures include:

• Adequate hydration.

• Regular bladder emptying.

• Early diagnosis and treatment of urinary symptoms.

• Screening and management of urinary tract abnormalities.

• Appropriate follow-up after treatment.

• Good control of diabetes mellitus.

• Avoidance of unnecessary urinary catheterization.