The Surprising Reasons You May Be Feeling Constipated

It could be a medication you're taking, a change in your routine, or even a combination of factors.

Woman having video consult with doctor about constipation

Constipation is a common problem.¹ Being constipated can lead to hard, dry, lumpy stools; difficulty passing stool; or incomplete bowel movements. It may mean having infrequent stools. (For some people, fewer than three bowel movements in a week may be a sign of constipation.)², ³

You can get constipated for different reasons, some more surprising than others.¹

What Causes Constipation?

Constipation may have a single cause or multiple causes at once.

For example, it can be a consequence of partially digested food moving too slowly through the colon (part of the large intestine). It's the colon's job, in part, to remove water from waste. But if the transit of waste through your digestive system is sluggish, the colon can absorb too much water. Stool becomes hard, dry, and difficult to pass in a bowel movement.⁴

Less often, constipation is a sign of a bowel blockage.⁴

Factors that might lead to constipation include use of certain supplements or medications, functional disorders, pregnancy, lifestyle factors, and even a change in routine.

Dietary supplements

Dietary supplements are natural products that may include minerals, vitamins, herbs, or probiotics. Studies suggest certain supplements, like calcium, may cause constipation.⁵, ⁶

If you experience constipation with calcium supplements, it may be helpful to spread the dose throughout the day or take it with food. It may also be helpful to change the kind of calcium you take.⁶

Iron is another potential culprit. A 2021 review found that taking iron may cause a variety of symptoms, including constipation or diarrhea.⁶

Multivitamins contain a variety of vitamins and minerals, and some of these ingredients (such as calcium and iron) may cause constipation in some people.⁷


Numerous medications can potentially cause constipation as a side effect. Among them, the National Institute of Diabetes and Digestive and Kidney Diseases singles out:⁸

  • Narcotic pain medicines
  • Some antidepressants
  • Antacids that contain calcium or aluminum
  • Diuretics
  • Medicines used to treat Parkinson's disease
  • Medicines used to prevent seizures (called anticonvulsants)
  • Drugs that relieve muscle spasms (antispasmodics or anticholinergics)


If you're not eating enough whole grains, fruits, or vegetables, don't be surprised if you have difficult or irregular bowel movements. A diet low in fiber can lead to constipation.¹

Prepared and processed foods (which may include frozen meals, fast food, and snacks) tend to be lower in fiber. If you're already constipated, these may be foods to avoid or consume less often.¹, ⁹

Drinking enough water is also important for keeping regular bowel habits. People who don't drink enough fluids may experience constipation.⁹

Irritable bowel syndrome

Irritable bowel syndrome (IBS) is a gastrointestinal disorder that can cause abdominal pain with changes in bowel habits. Some people find that defecating relieves their cramping pain. Others find that it makes it worse.¹⁰

With IBS, you can have constipation, diarrhea, or both. If you have mostly hard stools, you may have IBS with constipation, or IBS-C. Some people have IBS with mixed bowel patterns—sometimes their stool is hard, and sometimes it's loose.¹⁰

It is unclear what causes IBS, but experts believe a connection between the brain and the gut may play a role.⁸


Constipation is common in pregnancy. The American College of Obstetricians and Gynecologists states that it may be more common toward the end of pregnancy.¹¹

One possible reason: High levels of hormones during pregnancy. These hormones can slow digestion and relax muscles in the bowel, making you feel constipated. Another factor: An expanding uterus. As that organ stretches during pregnancy, it can put pressure on the bowel.¹¹ And that can slow down bowel movements.¹²

Pelvic floor dysfunction

The pelvic floor consists of muscles and tissue that support your pelvic organs (including your bladder and rectum). When the muscles and tissues in the pelvic floor tighten or relax inappropriately, it can be difficult for stool to pass.¹³

Retraining the pelvic floor muscles through physical therapy can help with this.¹

Changes to routine

Disruptions to everyday routines as well as changes that occur over time can leave you feeling constipated. If your bowel habits are altered, consider possibilities such as:⁸

  • The effects of getting older¹⁴
  • Travel-related changes
  • Meal-related changes (in other words, what you eat and how much you are eating)
  • The effects of medication changes

Lack of exercise

A sedentary lifestyle and not getting enough exercise can lead to constipation. Staying active is important when possible.⁹

Staying in bed or being inactive for extended periods due to illness or recovery from surgery may also contribute to constipation. In this instance, healthcare providers may prescribe medicine to help prevent constipation.⁹

When to See a Healthcare Provider

Many cases of constipation can be successfully treated at home through diet, increased fiber, fluids, and medications, like laxatives or stool softeners.¹⁵

It may be a good idea to reach out to a healthcare provider if you are constipated and have symptoms such as:³

  • Nausea
  • Vomiting
  • Bloating
  • No bowel movement in three days (and that's unusual for you)
  • Stomach pain
  • Blood in your stool


Lots of things can lead to constipation. Taking vitamins and supplements or other medications can sometimes lead to discomfort. Other times, underlying medical conditions, pregnancy, life changes, or changes in your usual routine can lead to constipation. If you're uncomfortable or having concerning symptoms, don't hesitate to seek help.


  1. American Gastroenterological Association. Constipation.
  2. MedlinePlus. Constipation.
  3. MedlinePlus. Constipation – self care.
  4. National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms and Causes of Constipation.
  5. Moses G. The safety of commonly used vitamins and minerals [published correction appears in Aust Prescr. 2021 Dec;44(6):209]. Aust Prescr. 2021;44(4):119-123. doi:10.18773/austprescr.2021.029
  6. NIH Office of Dietary Supplements. Calcium Fact Sheet for Consumers.
  7. NIH Office of Dietary Supplements. Multivitamin/Mineral Supplements.
  8. National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms & Causes of Constipation.
  9. National Institute of Diabetes and Digestive and Kidney Diseases. Eating, Diet, & Nutrition for Constipation.
  10. UpToDate from Wolters Kluwer. Clinical manifestations and diagnosis of irritable bowel syndrome in adults.
  11. American College of Obstetricians and Gynecologists. What can help with constipation during pregnancy?
  12. Office on Women's Health. Body changes and discomforts.
  13. Grimes WR, Stratton M. Pelvic Floor Dysfunction. [Updated 2022 Jun 27]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-.
  14. Schuster BG, Kosar L, Kamrul R. Constipation in older adults: stepwise approach to keep things moving. Can Fam Physician. 2015;61(2):152-158
  15. National Institute of Diabetes and Digestive and Kidney Diseases. Treatment for constipation.
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