What are the treatment options for constipation during pregnancy?

Treatment of Constipation in Pregnancy

For constipation during pregnancy, start with dietary fiber (30 g/day) and adequate hydration, then escalate to polyethylene glycol (PEG) or lactulose as first-line pharmacological therapy if dietary measures fail after one week. 1, 2

Stepwise Treatment Algorithm

Step 1: Non-Pharmacological Interventions (First-Line)

• Increase dietary fiber to approximately 30 g/day through fruits (prunes, raisins, apples, pears), vegetables (broccoli, leafy greens, sweet potatoes), whole grains, and legumes 1, 2, 3
• Aim for 3-4 servings of fruits and 3-4 servings of vegetables daily (1 medium fruit, 1/2 cup cut-up fruit, 1 cup raw leafy vegetables, or 1/2 cup cooked vegetables per serving) 2
• Ensure adequate fluid intake, particularly water, to soften stools 2, 3
• Allow sufficient time for bowel movements and use relaxation techniques to avoid straining 2, 3

Step 2: Bulk-Forming Agents (If Dietary Measures Ineffective After 1 Week)

• Psyllium husk (Metamucil) or methylcellulose are safe during pregnancy due to minimal systemic absorption 1, 2, 3
• These agents improve stool viscosity and transit time while increasing bulk 2
• Caution: Excessive fiber can cause maternal bloating 2

Step 3: Osmotic Laxatives (Preferred Pharmacological First-Line)

• Polyethylene glycol (PEG) 17g daily can be safely administered during pregnancy and is preferred over lactulose 1, 2, 3, 4
• PEG shows advantages including faster onset of bowel action and fewer flatulences compared to lactulose 4
• Lactulose is also safe but may cause more bloating than PEG 1, 2
• A 2004 study demonstrated PEG-4000 significantly increased evacuation episodes per week (from 1.66 to 3.16) and resolved constipation in 73% of pregnant women 5
• Magnesium hydroxide 400-500 mg daily is considered safe and effective 3

Step 4: Stimulant Laxatives (Use Cautiously, Short-Term Only)

• Bisacodyl 5-10 mg daily or senna should be used cautiously and only for short-term relief when other methods fail 1, 3, 6
• Evidence shows stimulant laxatives are more effective than bulk-forming laxatives for improvement in constipation (RR 1.59,95% CI 1.21-2.09), but cause significantly more abdominal discomfort (RR 2.33) and diarrhea (RR 4.50) 7
• Recommended in second and third trimester only if PEG/lactulose fails, due to concerns about tenesmus and preterm birth 4
• FDA labeling advises asking a doctor before use if pregnant 6

Special Considerations

For Severe Constipation or Immediate Relief

• Glycerin suppository may be considered for immediate relief if patient is severely uncomfortable 3
• Suppositories are preferred first-line therapy when digital rectal exam identifies a full rectum or fecal impaction 1

For Associated Hemorrhoids

• Hydrocortisone foam has been shown to be safe in the third trimester for symptomatic relief 2, 3
• Hemorrhoids occur in approximately 80% of pregnant women 2

Hospitalization Criteria

• Severe dehydration or inability to tolerate oral intake requires hospitalization for IV fluid replacement 8
• Implement anticoagulant thromboprophylaxis during hospital stay 3
• Transfer to tertiary center with gastroenterology and high-risk obstetrics if severe constipation requires hospitalization 3

Important Caveats and Pitfalls

Avoid these interventions:

• Bulk laxatives (psyllium) are NOT recommended for opioid-induced constipation if that is the underlying cause 1
• Magnesium and sulfate salts can lead to hypermagnesemia and should be used cautiously in renal impairment 1
• Stimulant laxatives should not be used long-term (>1 week) to avoid dehydration or electrolyte imbalances 6, 9, 10
• Enemas are contraindicated in patients with recent colorectal/gynecological surgery, recent anal trauma, or recent pelvic radiotherapy 1

Monitoring and Follow-Up

• Reassess bowel movement frequency and consistency after initiating treatment 3
• Goal: achieve soft, formed stools every 1-2 days 3
• Adjust treatment based on response, escalating through the algorithm as needed 3

Quality of Evidence

The 2024 AGA guideline 1 and 2025 Praxis summaries 2, 3 provide the strongest and most recent recommendations. A 2015 Cochrane review found insufficient high-quality evidence, with only moderate-quality data supporting fiber supplementation and stimulant laxatives, though the latter caused more side effects 7. The recommendation for PEG as first-line pharmacological therapy is based on guideline consensus and a small but positive 2004 trial 5.