Why Is My Poop Black While Pregnant? Causes and When to Worry

Black poop during pregnancy is most often caused by iron supplements, which are commonly prescribed to prevent or treat anemia. Certain foods like blueberries, black licorice, or beets can also darken stool. However, black, tarry, sticky stool with a foul odor may indicate bleeding in the upper digestive tract and requires prompt medical evaluation.

Common Causes of Black Stool in Pregnancy

Pregnancy brings many changes to your body, including your digestive system. Black stool can be alarming, but it is usually harmless. The most common reasons are:

• Iron supplements: Iron is often prescribed during pregnancy to prevent or treat anemia. Your body does not absorb all the iron, and the unabsorbed iron can turn your stool dark green or black. This is a normal side effect and not a cause for concern.
• Dietary factors: Eating dark-colored foods such as blueberries, black licorice, beets, or iron-rich foods like red meat and spinach can temporarily darken your stool.
• Medications: Some medications, like Pepto-Bismol (bismuth subsalicylate), can turn stool black. However, Pepto-Bismol is generally not recommended during pregnancy, so check with your doctor before taking it.

According to Cloudnine Care, black stool from iron supplements is common and usually not a problem. If you are concerned, continue taking your supplements as prescribed and discuss any side effects with your healthcare provider.

When Black Stool Could Signal a Problem

In rare cases, black stool during pregnancy can be a sign of gastrointestinal bleeding. Bleeding in the upper digestive tract (esophagus, stomach, or first part of the small intestine) can cause stool to appear black and tarry because the blood is digested as it passes through. This type of stool is often described as having a foul odor and a sticky consistency. Our breakdown of Bacterial Vaginosis in Women: Causes and Care covers the related details.

Possible causes of upper GI bleeding include gastritis, peptic ulcers, or tears in the esophagus from severe vomiting. If you have black, tarry stools along with any of the following symptoms, seek medical attention immediately:

• Dizziness or lightheadedness
• Abdominal pain or cramping
• Vomiting blood or material that looks like coffee grounds
• Weakness or fatigue
• Rapid heartbeat
• Pale skin

MyHealth Alberta notes that black stools may mean blood in the digestive tract and that you may need treatment right away. If you experience any of these warning signs, contact your healthcare provider or go to the emergency room.

How to Tell the Difference: Iron vs. Bleeding

It can be difficult to distinguish between black stool caused by iron supplements and black stool caused by bleeding. Here are some clues:

• Color: Iron supplements often cause dark green or black stool, sometimes with a greenish tint. Bleeding in the upper GI tract typically causes jet-black stool, like tar.
• Consistency: Iron-related stool is usually normal or slightly harder. Bleeding-related stool is often sticky, tarry, or loose.
• Odor: Iron supplements do not usually change the stool odor. Bleeding in the digestive tract can cause a foul, unusually strong odor.
• Other symptoms: Iron supplements may cause mild constipation, but bleeding may be accompanied by abdominal pain, dizziness, or weakness.

If you are unsure, it is always best to contact your healthcare provider. They can perform tests, such as a fecal occult blood test, to check for hidden blood in your stool.

Managing Black Stool from Iron Supplements

If your black stool is due to iron supplements, you do not need to stop taking them unless advised by your doctor. Iron is crucial for preventing anemia, which is common in pregnancy. However, you can take steps to minimize side effects:

• Take iron supplements with food to reduce stomach upset, but avoid taking them with calcium-rich foods (like milk or cheese) or antacids, as calcium can interfere with iron absorption.
• Drink plenty of water and eat high-fiber foods to prevent constipation, another common side effect of iron.
• Do not take more than the prescribed dose. Excess iron can be harmful.
• If constipation or dark stools bother you, talk to your doctor about alternative iron formulations, such as slow-release or lower-dose options.

Nisha Nursing Home explains that black stool from iron is normal and safe because the body does not absorb all the iron. Continuing your supplement as directed is important for your health and your baby's development.

Other Bowel Changes During Pregnancy

Pregnancy hormones can affect your entire digestive system. Besides black stool, you may notice:

• Constipation: Increased progesterone slows down bowel movements, leading to harder stools and straining.
• Hemorrhoids: Straining from constipation can cause swollen veins in the rectum, which may bleed and appear as bright red blood on toilet paper or in the stool.
• Changes in stool color: Stool may vary from green to yellow depending on diet and how quickly food moves through your intestines.

According to Ubie Health, iron commonly turns stool dark green or black, which is normal. However, black, tarry, sticky stool with a strong odor may signal bleeding in the digestive tract and should be evaluated.

When to Call Your Doctor

While black stool is often harmless, you should contact your healthcare provider if:

• The black color persists even after stopping iron supplements or changing your diet (but do not stop iron without medical advice).
• Your stool is black and tarry with a foul odor.
• You have other symptoms like abdominal pain, vomiting, dizziness, or weakness.
• You notice blood in your stool (bright red or dark) or black specks that look like coffee grounds.
• You feel faint or have a rapid heartbeat.

These could be signs of a more serious condition that needs prompt treatment. Your doctor can perform tests to determine the cause and ensure both you and your baby are healthy.

Remember, every pregnancy is unique. What is normal for one person may not be for another. Always discuss any concerns with your healthcare provider, who knows your medical history and can give personalized advice.