constipation.
last revised · reviewed 2026-07-05
Constipation affects up to 4 in 10 pregnant women, because progesterone relaxes the muscles of the gut and slows digestion right down. More fibre, more fluids, and regular gentle movement resolve most cases; safe laxatives exist if they don't.
what it feels like
Bowel movements become infrequent, hard, and effortful, often with bloating, wind, and a heavy or incomplete feeling afterwards. It can start surprisingly early — within weeks of conception — and iron supplements often make it noticeably worse.
why it happens
Progesterone relaxes smooth muscle everywhere, including the intestines, so food travels more slowly and more water is absorbed from the stool along the way. Later in pregnancy the growing uterus also physically crowds the bowel. Iron in pregnancy vitamins compounds the effect for many women.
what helps
- Aim for high-fibre foods daily — wholegrains, fruit with skins, vegetables, beans, and lentils
- Drink plenty of water — fibre without fluid can make things worse
- Move daily — even a 20 to 30 minute walk stimulates the bowel
- Try a footstool under your feet on the loo, so knees sit higher than hips
- Don't ignore the urge to go — delaying makes stools harder
- Prunes, prune juice, and kiwi fruit have genuine evidence behind them
- If diet isn't enough, ask your midwife, doctor, or pharmacist about fibre supplements or lactulose, which are considered safe in pregnancy
when to call your midwife or doctor
- Constipation with severe tummy pain, vomiting, or a swollen abdomen — call your midwife or doctor
- Blood in your stool that is more than a smear from a small tear or piles
- No bowel movement for a week despite fluids, fibre, and movement
- Alternating constipation and diarrhoea, or pain that doesn't ease after going
This page is general information, not a diagnosis. When in doubt, call — no midwife has ever minded a careful question.
common questions
Why does pregnancy cause constipation so early?
Progesterone rises from the moment of conception and relaxes the muscle of the bowel wall, slowing everything down. That is why constipation can appear in the first weeks — long before the uterus is big enough to press on anything.
Which laxatives are safe in pregnancy?
Bulk-forming fibre supplements and osmotic laxatives such as lactulose are generally considered safe in pregnancy, and are the usual first choice after diet and fluids. Avoid stimulant laxatives unless your doctor or midwife specifically recommends them — always confirm before taking anything.
Could my iron tablets be causing it?
Very possibly — iron supplements are a well-known cause of constipation and hard, dark stools. Don't stop iron that has been prescribed, but do tell your midwife or doctor; a different preparation or dose schedule often solves the problem.
read it in context
Constipation tends to show up around these weeks of pregnancy:
related symptoms
- Cramping in early pregnancy
Mild, period-like cramping is common and usually normal in early pregnancy — the womb is growing and its supporting ligaments are stretching.
- Swelling (oedema)
Gradual swelling of the feet, ankles, and fingers — oedema — is normal in later pregnancy, caused by extra fluid and the uterus slowing blood return from the legs.
- Discharge changes
More vaginal discharge than usual is normal throughout pregnancy — healthy discharge is clear or milky white, mild-smelling, and increases as pregnancy progresses.
know what's normal, week by week
elara tracks your symptoms alongside your weeks.
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