What is the most common cause of sepsis in pregnant patients?

Most Common Cause of Sepsis in Pregnant Patients

Urinary tract infections (UTIs) are the most common cause of sepsis in pregnant patients, with Escherichia coli being the predominant pathogen. 1, 2

Epidemiology and Risk Factors

• UTIs affect approximately 2-15% of pregnant women, making them the most common bacterial infection during pregnancy 1
• Physiological changes during pregnancy increase the risk of UTIs progressing to sepsis, including:
  • Urinary stasis due to pregnancy-induced changes in the urinary tract 3
  • Hormonal changes affecting urinary tract function 4
• Specific risk factors that increase the likelihood of UTIs progressing to urosepsis include:
  • Anemia (OR 2.622,95% CI 1.220-5.634) 5
  • 2nd-3rd grade hydronephrosis (OR 6.581,95% CI 2.802-15.460) 5
  • Fever over 38°C (OR 11.612,95% CI 4.804-28.07) 5

Pathophysiology

• E. coli is the most common causative organism in both symptomatic and asymptomatic bacteriuria during pregnancy 4
• Other common pathogens include:
  • Group B Streptococcus (GBS) 2
  • Group A Streptococcus 2
• Untreated asymptomatic bacteriuria can progress to acute pyelonephritis in up to 30% of pregnant women 4

Clinical Presentation

• The most common presenting symptoms of maternal sepsis include:
  • Hypothermia or hyperthermia 2
  • Tachycardia 2
• Laboratory findings typically show:
  • Abnormal white blood cell count (either elevated or decreased) 2
  • Elevated lactate levels 2
• Sepsis in pregnancy requires modified diagnostic criteria due to normal physiologic changes of pregnancy 6

Maternal and Fetal Complications

• Maternal complications of urosepsis include:
  • Increased risk of preeclampsia 4
  • Higher rates of obstetric transfers due to fetal distress (22.7% vs. 1.2% in non-septic UTIs) 5
• Fetal complications include:
  • Preterm birth 1, 4
  • Intrauterine growth restriction 4
  • Low birth weight 1, 4

Prevention and Screening

• Screening for asymptomatic bacteriuria with a single urine culture in the first trimester is recommended 1
• Early identification and treatment of UTIs can prevent progression to sepsis 2
• Patient education about signs and symptoms of UTIs and sepsis should be part of routine prenatal and postpartum care 2

Management Considerations

• Pregnant women with urosepsis often require urological interventions (87.9% vs. 36% in non-septic UTIs) 5
• Preferred antimicrobials for pyelonephritis include:
  • Amoxicillin combined with an aminoglycoside 1
  • Third-generation cephalosporins 1
  • Carbapenems in severe cases 1
• For less severe UTIs, shorter courses of β-lactams, nitrofurantoin, or fosfomycin are preferred 1

Special Considerations

• Approximately half of sepsis cases in peripartum women occur in the postdischarge period, highlighting the importance of vigilance during this time 6
• Lateral positioning in pregnant patients beyond 20 weeks' gestation helps improve blood flow and oxygenation by reducing aortocaval compression 7
• Controlling maternal fever is important to reduce fetal oxygen consumption and prevent fetal tachycardia 7

Understanding that UTIs are the most common cause of sepsis in pregnancy should guide clinicians to maintain a high index of suspicion, implement appropriate screening protocols, and initiate prompt treatment to prevent maternal and fetal complications.