What is the best treatment for constipation during pregnancy?

Treatment of Constipation in Pregnancy

Start with dietary fiber (30 g/day) and adequate hydration, then escalate to polyethylene glycol (PEG) 17g daily if dietary measures fail after one week, as this is the safest and most effective pharmacological option during pregnancy. 1, 2

Initial Non-Pharmacological Management

First-line therapy should focus on lifestyle modifications:

• Increase dietary fiber to approximately 30 g/day through fruits, vegetables, whole grains, and legumes 1, 2, 3
• Aim for 3-4 servings of fruits and 3-4 servings of vegetables daily to achieve adequate fiber intake 2, 3
• Ensure adequate fluid intake, particularly water, to soften stools and improve transit time 2, 4, 3
• Allow sufficient time for bowel movements and use relaxation techniques to avoid straining 2, 4

Specific high-fiber foods to recommend:

• Prunes, raisins, apples, apricots, and pears for soluble and insoluble fiber 2
• Broccoli, collards, kale, spinach, and other leafy greens 2
• Sweet potatoes and lima beans for combined fiber and nutrients 2

Pharmacological Treatment Algorithm

Step 1: Bulk-Forming Agents (If dietary changes fail after 1 week)

• Psyllium husk (Metamucil) or methylcellulose are safe during pregnancy due to minimal systemic absorption 2, 4
• These agents improve stool viscosity and transit time while increasing bulk 2
• Important caveat: Excessive fiber can cause maternal bloating, so titrate dose appropriately 2

Step 2: Osmotic Laxatives (If bulk-forming agents fail)

• Polyethylene glycol (PEG) 17g daily is the preferred first-line pharmacological therapy 1, 2, 4, 3
• PEG can be safely administered during pregnancy and generally produces a bowel movement in 1-3 days 5
• Lactulose is also safe but may cause more bloating than PEG, so PEG is preferred 1, 2, 3
• Magnesium hydroxide 400-500 mg daily is considered safe and effective 4, 3

Important safety consideration: Magnesium salts can lead to hypermagnesemia and should be used cautiously in patients with renal impairment 3

Step 3: Stimulant Laxatives (Use cautiously, short-term only)

• Stimulant laxatives should generally be avoided as routine therapy but can be used cautiously for short-term relief when other methods fail 1, 2, 4
• Bisacodyl 5-10 mg daily or senna have been used extensively without clear evidence of harm, though safety data are conflicting 2, 4, 6
• The main concern is tenesmus potentially triggering preterm contractions, particularly in the third trimester 4
• The second trimester offers the safest window for more aggressive management if needed 4

Step 4: Immediate Relief Options

• Glycerin suppository may be considered for immediate relief if the patient is severely uncomfortable 4, 3

Special Considerations and Management of Complications

Hemorrhoid management:

• Approximately 80% of pregnant women develop hemorrhoids 2, 4
• Hydrocortisone foam is safe in the third trimester for symptomatic relief of associated hemorrhoids 2, 3

When to hospitalize:

• Severe dehydration or inability to tolerate oral intake requires hospitalization for IV fluid replacement 3
• Implement anticoagulant thromboprophylaxis during hospital stay to prevent venous thromboembolism 3

Critical Pitfalls to Avoid

• Do not use bulk laxatives for opioid-induced constipation if the patient is on pain medications 3
• Avoid enemas in patients with recent colorectal/gynecological surgery, anal trauma, or recent pelvic radiotherapy 3
• Stop PEG and seek medical attention if rectal bleeding, worsening abdominal pain, diarrhea, or need for use beyond 1 week occurs 5
• Avoid long-term use of osmotic and stimulant laxatives to prevent dehydration or electrolyte imbalances 7

Monitoring and Follow-Up

• Reassess bowel movement frequency and consistency after initiating treatment 4, 3
• Goal: achieve soft, formed stools every 1-2 days 4, 3
• Adjust treatment based on response, escalating through the algorithm as needed 3
• Evaluate for secondary causes including hypothyroidism, hypercalcemia, and iron supplementation effects if constipation is refractory 4