The Surgical Abdomen in Pregnancy: A Comprehensive Management Guide
Prompt diagnosis and appropriate therapy are crucial in pregnant patients with acute abdomen, with a low threshold for surgical intervention when clinically indicated to prevent increased morbidity and mortality for both mother and fetus. 1
Etiology and Epidemiology
- Approximately 1 in 451 pregnancies require surgical intervention for non-obstetric abdominal conditions 2
- Most common causes:
Physiological Changes in Pregnancy Affecting Diagnosis
- Displacement of abdominal organs by enlarging uterus
- Leukocytosis (normal in pregnancy)
- Nausea and vomiting (common in normal pregnancy)
- Decreased bowel motility due to progesterone effects
- Increased intra-abdominal pressure
Clinical Presentation and Red Flags
Alarming clinical signs requiring immediate attention:
- Tachycardia ≥110 beats per minute
- Fever ≥38°C
- Hypotension
- Respiratory distress with tachypnea and hypoxia
- Decreased urine output 1
Specific warning signs by condition:
- Internal hernia: Persistent epigastric pain, especially in patients with history of laparoscopic Roux-en-Y gastric bypass 1
- Bowel obstruction: Persistent crampy/colicky abdominal pain, vomiting, and abnormal stool transit 1
- Intestinal ischemia: Severe abdominal pain disproportionate to physical findings, history of cardiac failure or recent surgery 4
Diagnostic Approach
Laboratory Testing
- Complete blood count
- Comprehensive metabolic panel
- C-reactive protein (CRP) and/or procalcitonin
- Serum lactate levels
- Blood gas analysis
- Urinalysis 4
Imaging
Ultrasound:
- First-line imaging modality in pregnancy
- Particularly useful for gallbladder pathology, hepatic lesions, and free fluid
- Sensitivity 96.7%, specificity 85.7% 4
- Limitations: Operator-dependent, limited by gravid uterus, bowel gas
MRI:
CT scan:
Diagnostic Laparoscopy
- Has higher sensitivity and specificity than any radiological assessment
- Safe in all trimesters when performed by experienced surgeons 1, 5
- Should not be delayed when high clinical suspicion exists despite negative imaging 1
Management Approach
General Principles
Multidisciplinary team approach:
- Obstetrician
- General surgeon
- Anesthesiologist
- Neonatologist (if >24 weeks)
Timing of intervention:
- Do not delay surgical intervention when indicated, as complications relate more to disease severity and operative delay than to the procedure itself 2
- Ideally perform elective procedures in second trimester when possible
Perioperative considerations:
- Left lateral positioning to avoid aortocaval compression
- Fetal monitoring for viable pregnancies
- Thromboprophylaxis with low molecular weight heparin 4
- Tocolytics only if signs of preterm labor develop
Specific Management by Condition
Appendicitis
- Most common non-obstetric surgical emergency in pregnancy
- Laparoscopic approach preferred in first and second trimesters
- Open approach may be considered in late third trimester 5
Biliary Disease
- Conservative management for uncomplicated biliary colic
- Laparoscopic cholecystectomy for acute cholecystitis or recurrent symptoms 5
- ERCP with sphincterotomy for choledocholithiasis
Small Bowel Obstruction
- Initial conservative management with nasogastric decompression and IV fluids
- Surgical intervention if no improvement within 24-48 hours
- Particularly high risk in patients with history of bariatric surgery 1
- Pregnancy increases risk of internal hernia after bariatric surgery due to increased intra-abdominal pressure 1
Sigmoid Volvulus
- Rare but serious cause of obstruction in pregnancy
- Endoscopic detorsion as first-line treatment (may be less effective in third trimester)
- Surgical decompression if endoscopic approach fails
- High maternal (6-12%) and fetal (20-26%) mortality rates 1
Antepartum, Intrapartum, and Postpartum Management
Antepartum
- Fetal monitoring during and after surgical procedures
- Tocolytic therapy only if signs of preterm labor
- Continued antenatal care with increased surveillance
Intrapartum
- Cesarean delivery based on obstetric indications only, not due to prior abdominal surgery 1
- Timing of delivery should not be altered by recent non-obstetric surgery unless complications arise
Postpartum
- Vigilant monitoring for postoperative complications
- Early mobilization and thromboprophylaxis
- Definitive surgical management of conditions initially managed conservatively during pregnancy
Common Pitfalls and Avoidance Strategies
Delayed diagnosis:
- Do not attribute all abdominal pain to normal pregnancy
- Maintain high index of suspicion for surgical pathology
Overreliance on laboratory values:
- Normal WBC may not rule out surgical pathology (leukocytosis normal in pregnancy)
- Normal CRP alone does not exclude surgical disease 1
Radiation concerns:
- Do not withhold necessary imaging due to unfounded radiation fears
- Single CT poses minimal risk to fetus compared to untreated surgical condition 1
Hesitancy to operate:
- Delay in surgical intervention increases maternal and fetal morbidity
- Premature labor (21%) is the most common postoperative complication but can be managed with tocolysis 2
Inadequate positioning:
- Always position pregnant patients with left lateral tilt to prevent aortocaval compression
- Improper positioning can lead to maternal hypotension and decreased placental perfusion 1
By following these guidelines and maintaining a high index of suspicion for surgical pathology in pregnant patients with abdominal pain, clinicians can optimize outcomes for both mother and fetus.