Pregnancy commonly causes constipation due to hormonal, physical, and lifestyle factors that slow bowel movement and dry the stool.
Main reasons
- Hormones: Rising progesterone relaxes smooth muscle in the gut, slowing intestinal transit so more water is absorbed from stool, making it harder and drier. Estrogen shifts may also influence motility, but progesterone’s slowing effect is the primary clinical explanation.
- Uterine pressure: As pregnancy progresses, the enlarging uterus compresses portions of the colon, further slowing stool movement.
- Iron supplements: Prenatal vitamins often contain iron, which can firm stools and contribute to constipation.
- Routine changes: Less physical activity, lower fiber or fluid intake, and nausea-related dietary shifts can all worsen constipation.
What helps
- Hydration: Aim for regular fluid intake across the day; consider warm beverages to stimulate a bowel movement.
- Fiber: Gradually increase fiber from whole grains, fruits, vegetables, legumes, and consider a fiber supplement if needed.
- Movement: Gentle, regular activity like walking or prenatal yoga supports gut motility.
- Toilet habits: Respond to the urge promptly; allow unhurried time after meals, and consider a footstool to straighten the anorectal angle.
- Medications: Discuss options with a clinician before using laxatives; bulk-forming fiber and some stool softeners are commonly used in pregnancy, while stimulant laxatives or certain herbal products may not be appropriate.
When to seek care
- Persistent constipation despite lifestyle changes, severe abdominal pain, rectal bleeding, vomiting, or inability to pass gas/stool warrant medical evaluation.
- If iron supplements seem contributory, a clinician can advise on dosing, timing with food, or alternative formulations to reduce constipation while maintaining adequate iron.
In short, the combination of hormone-driven slowed gut motility, physical pressure from the growing uterus, iron in prenatal vitamins, and lifestyle changes makes constipation a frequent pregnancy symptom—usually manageable with fluids, fiber, movement, and targeted guidance.
