How is constipation managed during pregnancy?

Management of Constipation During Pregnancy

The optimal management of constipation during pregnancy follows a stepwise approach, beginning with lifestyle and dietary modifications, followed by bulk-forming agents, and then osmotic laxatives if needed. 1

Prevalence and Causes

• Constipation affects 20-40% of pregnant women, with symptoms typically worsening in the third trimester 1
• Primary causes include increased progesterone levels slowing gastrointestinal motility and mechanical compression of the rectum by the gravid uterus 1
• Hormonal, medication-related, anatomic, dietary, and metabolic changes also contribute to constipation during pregnancy 1

Treatment Algorithm

First-Line: Lifestyle and Dietary Modifications

• Increase dietary fiber intake to approximately 30 g/day through fruits, vegetables, whole grains, and legumes 1
• Ensure adequate fluid intake, particularly water, to soften stools 1
• Allow sufficient time for bowel movements and avoid straining 1
• Use relaxation techniques during defecation 1
• These conservative measures should be tried for at least one week before moving to second-line treatments 1

Second-Line: Bulk-Forming Agents

• If dietary modifications are ineffective after one week, add bulk-forming agents like psyllium husk or methylcellulose 1
• These agents are safe during pregnancy due to minimal systemic absorption 1
• Soluble fiber (psyllium) improves stool viscosity and transit time in addition to increasing bulk 1
• Fiber supplementation has been shown to significantly increase stool frequency (by approximately 2.24 times per week) compared to no intervention 2
• Continue these for 1-2 weeks before considering third-line options 1

Third-Line: Osmotic Laxatives

• If bulk-forming agents provide inadequate relief after 1-2 weeks, add an osmotic laxative 1
• Polyethylene glycol (PEG) and lactulose are safe osmotic laxatives during pregnancy 1, 3
• PEG 4000 (10g twice daily) may provide faster relief of constipation symptoms compared to lactulose (15mL twice daily) 3
• Magnesium hydroxide at 400-500 mg daily is another safe option for persistent constipation 1
• Use osmotic laxatives only for short-term or occasional use to avoid dehydration or electrolyte imbalances 4

Treatments to Use with Caution or Avoid

• Stimulant laxatives should generally be avoided during pregnancy due to conflicting safety data 1
• However, if used, stimulant laxatives appear more effective for improvement of constipation than bulk-forming laxatives, but with increased risk of abdominal discomfort and diarrhea 2
• Osmotic laxatives should be used with caution in patients with renal insufficiency 1

Management of Associated Conditions

• Hemorrhoids occur in approximately 80% of pregnant women, more commonly during the third trimester 1
• For hemorrhoid treatment, hydrocortisone foam has been shown to be safe in the third trimester 1

Important Considerations and Pitfalls

• Most cases of constipation during pregnancy are simple and can be managed with conservative measures 5
• Extensive evaluation is usually unnecessary for women who present with constipation for the first time during pregnancy 6
• However, women with pre-existing constipation that worsens during pregnancy should be fully evaluated after delivery 5
• When using pharmacological agents, always weigh benefits against possible adverse effects 6
• Avoid excessive use of osmotic laxatives like lactulose which can cause maternal bloating 1
• For persistent or severe symptoms despite appropriate management, consider evaluation for other causes of constipation 1