Does C-Section Increase Risk of Small Bowel Obstruction?
Yes, cesarean section does increase the risk of small bowel obstruction (SBO), though the absolute risk remains very low at approximately 0.1%.
Magnitude of Risk
The risk of adhesive SBO following cesarean section is significantly lower compared to other abdominal procedures, but it is not zero 1:
- C-section: 0.1% incidence of subsequent SBO
- Open gynecological procedures carry much higher risks: open adnexal surgery (23.9%), open total abdominal hysterectomy (15.6%)
- For comparison, open colectomy has 9.5% incidence and ileal pouch-anal anastomosis has 19.3% incidence 1
The laparoscopic advantage seen in other procedures does not apply to cesarean delivery, as it is inherently an open abdominal procedure 1.
Mechanism and Timing
Adhesions form as a consequence of peritoneal injury during any abdominal surgery 2:
- Most SBO cases occur within the first 2 years post-surgery, though new cases can develop many years later 2
- Adhesive obstruction after cesarean occurs more frequently in advanced pregnancy during subsequent pregnancies: 6% in first trimester, 28% in second trimester, 45% in third trimester, and 21% in puerperium 3
- Acute intestinal pseudo-obstruction can occur specifically during puerperium following C-section 3
Clinical Presentation
When SBO develops after cesarean section, typical symptoms include 3:
- Abdominal pain (98% of cases)
- Vomiting (82%)
- Constipation (30%)
- Abdominal tenderness on palpation (71%)
- Abnormal peristalsis (55%)
Unusual Complications
Surgical hemostatic agents (gelatin sponges) placed during cesarean can cause early postoperative SBO through adhesion formation to bowel loops 4. This should be considered in the differential diagnosis when SBO symptoms develop in the immediate postoperative period 4.
Management Approach
When SBO occurs after prior cesarean 5:
- Initial conservative management is appropriate unless signs of peritonitis, strangulation, or bowel ischemia are present 2
- A 72-hour trial of non-operative management is considered safe 2
- Laparoscopic adhesiolysis can be performed in selected patients with favorable anatomy (≤2 prior laparotomies, no previous median incision, single adhesive band) 2, 5
- Conversion to open surgery is mandatory if dense adhesions, inability to visualize obstruction site, iatrogenic perforation, or bowel necrosis are encountered 5
Risk Factors for Adhesion Formation
Factors that increase adhesion risk during any abdominal surgery include 2:
- Foreign body reaction (starch-powdered gloves, mesh)
- Type of energy device used (monopolar electrocautery causes more peritoneal injury than bipolar or ultrasonic devices)
- Separate closure of peritoneum
- Spillage of contents during surgery
Prevention Considerations
Adhesion barriers (hyaluronate carboxymethylcellulose) have shown efficacy in reducing ASBO risk in colorectal surgery 2, though specific data for cesarean sections is limited. Young patients have the highest lifetime benefit from adhesion prevention given their long-term risk exposure 2.
Prognosis During Pregnancy
If SBO develops during a subsequent pregnancy after prior cesarean, the prognosis is concerning 3:
- Fetal mortality: 36% in second trimester, 64% in third trimester
- Maternal mortality: 6%
- If fetal anoxia develops, C-section should be performed before surgical intervention for the obstruction 3