Constipation is very common in pregnancy: up to 2 in 5 pregnant people have it. Stools can become hard, dry and painful to pass, and it can leave you uncomfortable and bloated. It is common, and it can usually be helped. This guide covers why it happens, why the right first step is different for everyone, how iron tablets fit in, and when to see your doctor.
At a glance
- Pregnancy hormones slow your gut down, which is why constipation is so common.
- Fluid, fibre, iron and other supplements, medicines, movement and routine can all play a part.
- Which of these is behind yours decides what to change first, so the answer differs from person to person.
- Some supplements, including iron, can cause constipation. Ask your doctor before changing them.
- Check with your doctor or pharmacist before taking any laxative.
Why it happens in pregnancy
The pregnancy hormone progesterone relaxes muscles and slows the movement of food through your gut. Other common contributors are medicines for nausea or heartburn, some multivitamins and iron supplements, not enough fibre or a lot of high-fat food, less exercise, and stress or changes in routine.
Iron deserves a special mention. A large review of trials found that the common iron tablet ferrous sulfate significantly increases gut side effects compared with a placebo. If you started iron and your bowels changed, that may be why. Your doctor may be able to change the dose or type, so ask rather than stopping on your own.
Why the first step is different for everyone
Fluid and fibre are often part of the story, but they are rarely all of it. For one person the main driver is iron, for another it is a low-fibre routine, and for someone else it is the medicine they take for nausea or heartburn. Piling on more fibre without knowing which it is can make bloating worse, and it can leave the real cause untouched.
Working out what to change first, and in what order, depends on what you eat, what you take and how your days run.
That is what the consult is for. We look over a few days of your food and your supplements, work out where your gaps are, and plan the changes that fit your routine without adding to the bloating. Constipation Mini Consult: 20 minutes, $39, by telehealth →
Laxatives and fibre supplements
If food and habits are not enough, your doctor may suggest a fibre supplement or a laxative. Not all laxatives are recommended in pregnancy and doses can differ, so always check with your doctor or pharmacist before starting one. The research on treating constipation in pregnancy is small: a Cochrane review found only a few trials, which is another reason to get advice rather than experiment.
When to see your doctor
See your doctor if your constipation is severe (for example 3 or more days between bowel movements, tummy pain, or long periods of straining), if it is not improving with simple changes, or if you are worried. Get urgent care if you have constipation with unexplained weight loss, bleeding from your bottom or blood in your stool, severe tummy pain, cramping or bloating, or vomiting.
Free one-page guide: Constipation in pregnancy, with the warning signs and questions to bring to your dietitian. Print it or keep it on your phone.
Download the PDFWhere a dietitian helps
Send a few days of food before we talk, and we can analyse your fibre and fluid, look at how your supplements fit in, and plan changes that don’t make the bloating worse.
The Constipation Mini Consult is 20 minutes with an Accredited Practising Dietitian, by telehealth from anywhere in Australia, for $39.
About the constipation mini consult →Common questions
Why am I constipated in pregnancy?
Pregnancy hormones slow your gut down. Some medicines and supplements, including iron, low fibre intake, less exercise and changes in routine can all add to it.
What should I change first for constipation in pregnancy?
It depends on what is behind it. Fluid, fibre, iron and other supplements, medicines, movement and routine can all play a part. A dietitian can look at your food, supplements and habits and work out where to start. See your doctor if it is severe or not improving.
Do iron tablets cause constipation?
They can. A large review found the common iron tablet ferrous sulfate significantly increases gut side effects. Ask your doctor whether a different dose or type would suit you, rather than stopping it yourself.
Is it safe to take a laxative while pregnant?
Some are and some are not recommended, and doses may differ. Check with your doctor or pharmacist before taking any laxative in pregnancy.
When should I see a doctor about constipation?
If it is severe, not improving with simple changes, or you are worried. Get urgent care if you also have bleeding, severe tummy pain, vomiting or unexplained weight loss.
Where this comes from
General information only, not personal advice. It does not replace your GP, midwife or obstetrician.
- Pregnancy, Birth and Baby (healthdirect Australia). Constipation during pregnancy. www.pregnancybirthbaby.org.au/pregnancy/health-conditions-and-complications/constipation-during-pregnancy
- Tolkien Z, Stecher L, Mander AP, Pereira DIA, Powell JJ. Ferrous sulfate supplementation causes significant gastrointestinal side-effects in adults: a systematic review and meta-analysis. PLOS ONE. 2015;10(2):e0117383. doi.org/10.1371/journal.pone.0117383
- Rungsiprakarn P, Laopaiboon M, Sangkomkamhang US, et al. Interventions for treating constipation in pregnancy. Cochrane Database of Systematic Reviews. 2015;CD011448. doi.org/10.1002/14651858.CD011448.pub2