Can a pregnant woman develop appendicitis?

Appendicitis in Pregnancy: Diagnosis and Management

Yes, pregnant women can develop appendicitis, which is actually the most common non-obstetric surgical emergency during pregnancy, affecting approximately 1 in 20 women of childbearing age who present with appendicitis. 1

Epidemiology and Clinical Presentation

• Appendicitis most commonly manifests in early to mid-pregnancy 1
• Pregnant women with appendicitis have similar clinical outcomes compared to non-pregnant women, but are:
  • More likely to undergo nonsurgical management 1
  • More likely to present with complicated (perforated or gangrenous) appendicitis 1
  • At higher risk of fetal loss when perforation occurs 1

Diagnostic Challenges

The diagnosis of appendicitis during pregnancy is particularly challenging due to:

• Physiological changes of pregnancy that can mimic appendicitis symptoms
• Displacement of the appendix by the growing uterus (especially in 2nd and 3rd trimesters)
• Limited utility of clinical symptoms alone for diagnosis

Clinical Assessment

• Laboratory tests and inflammatory markers (CRP) should always be requested in pregnant patients with suspected appendicitis 1
• Clinical scores alone (Alvarado, AIR, AAS) are not sufficient to diagnose appendicitis in pregnancy 1
• Symptoms that may indicate appendicitis in pregnancy:
  • Uterine contractions
  • History of diffuse or periumbilical pain migrating to the right lower quadrant 2

Imaging Recommendations

A stepwise diagnostic approach is recommended:

1. Ultrasound (first-line):

   • Combined transabdominal and transvaginal approach when possible
   • Sensitivity: 61.2%, specificity: 80% for appendicitis in pregnancy 1
   • Appendix visualization rates decrease with advancing gestational age (25% in first trimester vs 63% in third trimester) 1

2. MRI (second-line) when ultrasound is inconclusive:

   • No radiation exposure to fetus
   • High diagnostic accuracy: sensitivity 96.8%, specificity 99.2%, NPV 99.7% 1
   • Appendix non-visualization rate: approximately 30% 1
   • MRI can prevent unnecessary surgery in 88% of patients with inconclusive ultrasound 1

3. CT (last resort):

   • Consider low-dose CT with oral contrast when MRI is not immediately available
   • Recent studies show LDCT can be conclusive for appendicitis diagnosis in 83% of pregnant patients 1

Management Considerations

• Prompt diagnosis and treatment are essential to reduce risk of perforation
• Pregnant women with appendicitis have similar clinical outcomes as non-pregnant women 1
• Complications to be aware of:
  • Maternal morbidity is relatively low 3
  • Risk of premature delivery is increased with both confirmed appendicitis and negative appendectomy 3
  • First trimester appendectomy may be associated with higher risk of spontaneous abortion (33% in one study) 2
  • Second trimester appendectomy may lead to premature delivery in approximately 14% of cases 2

Pitfalls and Caveats

• Delay in diagnosis increases risk of perforation, which increases risk of fetal loss
• Negative appendectomy also carries risks for pregnancy outcomes
• The combination of ultrasound followed by MRI (when needed) is the most commonly used imaging approach (41% of cases) 1
• Appendix non-visualization on MRI should be reported as "low risk for appendicitis" rather than "indeterminate" when no ancillary signs of appendicitis are present 1

The key to managing appendicitis in pregnancy is prompt and accurate diagnosis using appropriate imaging, followed by timely intervention to minimize both maternal and fetal complications.