Causes and Risk Factors of Constipation

Most people experience constipation from time to time. It is often temporary and due to lifestyle factors or side effects of medication. Constipation that persists (chronic) can also be caused by a health condition, structural problems, or functional problems. It is also very common during pregnancy.

Constipation is defined as:

• Having fewer than three bowel movements a week
• Stools that are hard, dry, or lumpy
• Stools that are difficult or painful to pass
• A feeling that not all stool has passed
  

This article discusses the lifestyle, medical, and genetic causes of constipation. It also provides a detailed list of medications that can cause constipation.

Common Causes

The underlying mechanism behind constipation is the slow movement of stool through your large intestine (colon).

As food travels through the digestive system, it is broken down into fluid, nutrients, and waste. By the time it reaches the colon, most of the nutrients have been absorbed, leaving fluid and waste. The fluid is absorbed in the large intestine, turning the waste into stool.

However, if digestion stalls, the colon continues to absorb fluid. This, in turn, causes hard stools that are difficult to pass. What you eat, how much you move, and other lifestyle factors can impact how quickly or slowly food transitions through the digestive tract.

Diet

A top cause of constipation is diet. Eating too much dairy, high-fat meats, eggs, and sugar-containing sweets can lead to constipation. Dairy products, in particular, have a reputation for binding up stool. This includes cow's milk, cheese, and ice cream.

If you mostly eat processed foods, dairy, and meat, you are probably not getting enough insoluble fiber. Insoluble fiber—found in vegetables, fruits, beans, and whole grains—promotes the movement of food through your colon.

Not Enough Fluids

Constipation can also be caused by not consuming enough fluid. This is especially true in people who are getting enough fiber—water helps fiber work to prevent constipation.

How much water and other fluids you need a day varies by age and sex. The U.S. National Academies of Sciences, Engineering, and Medicine recommends a total daily intake that combines fluids from water, other beverages, and food. About 20% of our daily fluid intake comes from foods. The daily fluid recommendations for adults are:

• Women: 11.5 cups (2.7 liters) per day
• Men: 15.5 cups (3.7 liters) per day
  

Lifestyle Factors

Other lifestyle factors that can affect your bowel movements and lead to constipation include:

• Being sedentary most of the day
• Changes in your routine
• Ignoring urges to move your bowels
• Stress
• Travel
  

Medical Causes of Constipation

Different medical conditions, illnesses, functional problems, and medications cause constipation.

Health Conditions

Health conditions that can contribute to constipation include:

• Celiac disease
• Chronic idiopathic constipation
• Depression or anxiety
• Diabetes
• Diverticulitis
• Electrolyte deficiencies
• Fibromyalgia
• Irritable bowel syndrome (IBS)
• Pregnancy
  
• Thyroid disease
  

Medications

Medication is a common cause of constipation. Certain medications cause changes to the gastrointestinal tract that slow motility (movement of food through the gut) causing constipation. Medications that have a side effect of constipation include:

• Antacids containing calcium or aluminum
• Anticholinergic medications (antispasmodics)
• Antidepressants
• Antihistamines (allergy medications)
• Calcium channel blockers (for high blood pressure)
• Diuretics
• Opioid or narcotic pain medications
• Some seizure medications
• Some blood pressure medications
• Iron supplements
• Some herbal supplements

You may also develop constipation by taking too many laxatives or enemas in an attempt to treat constipation. Using these remedies repeatedly can result in dependence on them to the point that you no longer have normal bowel movements.

Structural Conditions

The following conditions involve a structural problem within the digestive system that can contribute to the symptom of constipation.

• Anal fissure
• Bowel obstruction
• Bowel stricture
• Rectocele (a bulge from the rectum into the vagina)

Pelvic Floor Dysfunction

Dyssynergic defecation is a form of pelvic floor dysfunction in which the muscles of the pelvic floor do not work as they should. A primary symptom of dyssynergic defecation is constipation.

Neurological Causes

Several neurological conditions can contribute to constipation. Some conditions affect the functioning of the muscles in the colon and rectum, which must contract to move stool. If the nerves that trigger these muscles are affected, it can result in constipation.

Neurological causes of constipation include:

• Autism
• Dysautonomia
• Multiple sclerosis
• Parkinson's disease
• Spinal cord injury
• Stroke

Cancer

Any cancer affecting the colon's functioning can cause constipation as well. It is important to note that colon cancer also typically presents itself with symptoms of weight loss, fatigue, and signs of blood in the stool:

• Colon cancer
• Rectal cancer

Genetics

Because constipation often runs in families, there may be some genetic predisposition to this condition. Families may also share environmental factors such as habits and similar diets. Children with chronic constipation often have family members who are constipated.

There is a rare genetic condition, Hirschsprung disease, in which the nerves required to move stool through the intestinal tract are absent. This can occur due to a chromosomal disorder or due to specific genetic combinations. In this disease, the symptoms are seen in the first two months of life.

Risk Factors

Several factors increase the risk of constipation. The condition is more common among those who:

• Are age 60 and older
• Are female
• Have an eating disorder
• Have a lower income level

Summary

Constipation can be caused by diet, not drinking enough fluids, not getting enough exercise, a change in your routine, medication, or a medical condition.

A Word From Verywell

If you are experiencing constipation on a regular basis, talk to your healthcare provider. It is important to accurately pinpoint what is going on and to establish a treatment plan. Your healthcare provider will work with you on developing the right management plan for you.