Treatment of Constipation in Pregnancy
Start with dietary fiber (30 g/day) and adequate hydration, then escalate to polyethylene glycol (PEG) 17g daily as first-line pharmacological therapy if dietary measures fail after one week. 1, 2
Initial Non-Pharmacological Management
- Increase dietary fiber to approximately 30 g/day through fruits (prunes, raisins, apples, pears, berries), vegetables (broccoli, leafy greens, carrots, sweet potatoes), whole grains, and legumes 1, 3, 2
- Aim for 3-4 servings of fruits and 3-4 servings of vegetables daily to achieve adequate fiber intake 1, 3
- Ensure adequate fluid intake, particularly water, to soften stools and improve transit time 1, 2
- Allow sufficient time for bowel movements and use relaxation techniques to avoid straining 2
Pharmacological Treatment Algorithm
First-Line Therapy
Polyethylene glycol (PEG) 17g daily is the preferred first-line pharmacological option if dietary changes fail after 1 week 1, 2, 4. PEG demonstrates faster onset of action and causes less bloating compared to alternatives 5, 4.
Alternative First-Line Options
- Lactulose is safe but may cause more bloating than PEG, making it a second choice 1, 2, 5
- Magnesium hydroxide 400-500 mg daily is safe and effective, but use cautiously in patients with renal impairment 1, 2
Second-Line Therapy
- Bulk-forming agents (psyllium husk or methylcellulose) have minimal systemic absorption and are safe during pregnancy 2, 6
- Note that excessive fiber can cause maternal bloating 2
Immediate Relief Option
- Glycerin suppository may be considered for immediate relief if the patient is severely uncomfortable 1
Management of Associated Complications
Hemorrhoids occur in approximately 80% of pregnant women with constipation 2. Hydrocortisone foam is safe in the third trimester for symptomatic relief of hemorrhoids 1, 2.
Critical Pitfalls to Avoid
- Do not use bulk laxatives for opioid-induced constipation if the patient is on pain medications 1, 2
- Avoid stimulant laxatives as first-line therapy due to conflicting safety data and risk of tenesmus potentially triggering preterm labor 2, 5
- Enemas are contraindicated in patients with recent colorectal/gynecological surgery, anal trauma, or recent pelvic radiotherapy 1, 2
- Use magnesium salts cautiously in renal impairment due to risk of hypermagnesemia 1
When to Hospitalize
Severe dehydration or inability to tolerate oral intake requires hospitalization for IV fluid replacement 1, 2. Implement anticoagulant thromboprophylaxis during hospital stay to prevent venous thromboembolism 1, 2.
Monitoring and Follow-Up
- Reassess bowel movement frequency and consistency after initiating treatment, with a goal of achieving soft, formed stools every 1-2 days 1, 2
- Adjust treatment based on response, escalating through the algorithm as needed 1, 2
- If constipation is refractory, evaluate for secondary causes including hypothyroidism, hypercalcemia, and iron supplementation effects 2