Constipation is a common issue that affects many people at some point.
It is often short-term and linked to lifestyle habits or the side effects of medications.
However, if constipation persists, it may be due to an underlying health condition, structural issues, or functional problems.
It is also frequently experienced during pregnancy.
What Is Constipation?
Constipation is typically characterized by the following symptoms:
- Fewer than three bowel movements per week
- Hard, dry, or lumpy stools
- Difficulty or pain when passing stools
- The sensation that not all stool has been passed
This article discusses the various lifestyle, medical, and genetic factors that contribute to constipation and lists medications that can cause the condition.
Common Causes of Constipation
The main cause of constipation is the slow movement of stool through the large intestine (colon).
As food moves through the digestive system, nutrients are absorbed by the time it reaches the colon, leaving waste and fluid.
The colon absorbs additional fluid, which solidifies the waste into stool.
However, when digestion slows, the colon absorbs too much fluid, leading to hard, dry stools that are difficult to pass.
Factors that influence the speed of digestion include diet, physical activity, and lifestyle choices.
Dietary Factors
Diet is one of the most common contributors to constipation. Excessive consumption of dairy, high-fat meats, eggs, and sugary foods can all slow digestion and contribute to constipation. Dairy products, especially cow’s milk, cheese, and ice cream, are known to harden stools.
A diet low in fiber—particularly insoluble fiber found in vegetables, fruits, beans, and whole grains—can also hinder the movement of food through the colon and result in constipation.
Inadequate Fluid Intake
Not drinking enough fluids is another major factor that contributes to constipation, particularly for individuals who consume a lot of fiber but don’t drink enough water. Proper hydration helps fiber function effectively, keeping stool soft and supporting regular bowel movements.
The U.S. National Academies of Sciences, Engineering, and Medicine recommend daily fluid intake as follows:
- Women: 11.5 cups (2.7 liters)
- Men: 15.5 cups (3.7 liters)
This total includes fluids from both beverages and food sources, with about 20% of daily fluid intake coming from food.
Lifestyle Factors
Other lifestyle factors affecting bowel health include:
- Being inactive for extended periods
- Sudden changes in routine
- Ignoring the urge to have a bowel movement
- High levels of stress
- Traveling, particularly across time zones
Medical Conditions That Can Cause Constipation
Several medical conditions and disorders can contribute to chronic constipation, including:
- Celiac disease
- Chronic idiopathic constipation
- Depression and anxiety
- Diabetes
- Diverticulitis
- Electrolyte imbalances
- Fibromyalgia
- Irritable bowel syndrome (IBS)
- Pregnancy
- Thyroid disease
Medications That Cause Constipation
Certain medications can slow down digestion and lead to constipation. Some common drugs associated with constipation include:
- Antacids containing calcium or aluminum
- Anticholinergic drugs (e.g., antispasmodics)
- Antidepressants
- Antihistamines (allergy medications)
- Calcium channel blockers (for high blood pressure)
- Diuretics
- Opioid painkillers
- Some seizure medications
- Iron supplements
- Some blood pressure medications
- Some herbal supplements
It’s also important to note that overusing laxatives or enemas in an attempt to treat constipation can lead to dependence, making it difficult for the body to have normal bowel movements without assistance.
Structural Problems
Certain structural issues within the digestive system can lead to constipation:
- Anal fissures (painful tears around the anus)
- Bowel obstructions or strictures (narrowing of the intestines)
- Rectocele (a bulge of the rectum into the vagina)
- Pelvic Floor Dysfunction, such as dyssynergic defecation, where the pelvic floor muscles do not function properly, making it difficult to pass stool.
Neurological Causes
Certain neurological conditions can interfere with the muscles and nerves responsible for bowel movements, leading to constipation. These conditions include:
- Autism
- Dysautonomia
- Multiple sclerosis
- Parkinson’s disease
- Spinal cord injuries
- Stroke
Cancer
Cancer affecting the colon or rectum can also contribute to constipation, often accompanied by other symptoms such as unexplained weight loss, fatigue, and blood in the stool. If these signs appear, it’s important to consult a healthcare provider.
Genetic Factors
Constipation often runs in families, suggesting genetic factors may play a role. Children with chronic constipation are more likely to have relatives with the same condition. Additionally, Hirschsprung disease, a rare genetic disorder, causes a lack of nerve cells in the intestines, leading to severe constipation in early life.
Risk Factors for Constipation
Several factors increase the likelihood of developing constipation:
- Age: People aged 60 and older are more prone to constipation.
- Gender: Women are more likely to experience constipation than men.
- Eating disorders: Conditions like anorexia and bulimia can disrupt digestion and lead to constipation.
- Socioeconomic factors: Individuals with lower income may have limited access to healthy food or healthcare, increasing the risk of constipation.