Black Poop in Pregnancy: Causes & When to Call Your OB/GYN

Key Takeaways:

Black poop in pregnancy may be caused by harmless triggers, such as iron supplements, medications containing bismuth (like Pepto-Bismol), or certain foods.

Tarry, black stools during pregnancy (or at any time) may indicate bleeding in the gastrointestinal tract. This is a sign of a potentially serious problem, so talk to your OB/GYN right away.

In a majority of cases, noticing dark stool while pregnant doesn’t indicate a problem with the fetus or a health condition that will affect the health of your baby. But it’s always worth a chat with your healthcare provider, just to make sure.

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How pregnancy changes your poop

Pregnancy brings about a wave of changes in your body, including shifts in your digestive system that can affect your bowel movements.

Is it normal for my stool to change during pregnancy? Yes, it’s perfectly normal to see changes in your stool when you’re expecting. These changes can appear as a different stool color, altered consistency, or more frequent diarrhea and/or constipation.

Your stool’s color won’t necessarily change during pregnancy. But certain factors like taking iron supplements, prenatal vitamins, or eating certain foods like blueberries and licorice could lead to darker, even black stools.

This color change is often harmless.

What is the color of your poop supposed to be during pregnancy? Normal poop is always light-to-medium brown. Poop may sometimes appear green (if you eat a lot of green leafy vegetables) or very dark to black (if you consume a lot of iron or eat dark-colored foods).

Hormonal changes in your body can have a notable impact on the consistency of your poop, too.

Progesterone, a hormone that increases during pregnancy, tends to relax smooth muscles throughout the body, including those in the digestive tract. This can slow down the digestive process, which often leads to constipation.

Constipation is a very common symptom in pregnancy, particularly in the third trimester.

Some pregnant women may experience more frequent bowel movements or diarrhea. This might be due to dietary changes, stress, or certain prenatal vitamins. In early pregnancy, cramping and bloating can also affect your bowel movements, making them less predictable than usual.

Causes of dark stool during pregnancy

1. Iron supplements

One of the common side effects of iron supplements is a change in stool color, often to a darker, sometimes even black shade. Typically, iron supplementation of 80 mg/day or more is associated with darker stools.

This happens when the mother’s body does not fully absorb the iron supplement. The unabsorbed iron passes through the digestive system, interacting with other substances and giving the stool its dark hue.

Iron supplements support the health and well-being of both the mother and the unborn baby during pregnancy.

They aid in the production of hemoglobin, a protein in red blood cells that transports oxygen throughout the body. As the blood volume increases by up to 50% during pregnancy, pregnant moms need sufficient iron levels to meet this heightened demand and prevent conditions such as anemia.

Iron supplements also support the growing fetus and placenta, contributing to the healthy development of the baby.

However, If you’ve noticed your stool turning darker after starting iron supplements, there’s no need to panic. Dark stool due to iron supplementation is generally normal and not a cause for concern. It is a well-documented side effect that many pregnant women experience.

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2. Eating certain foods

Eating specific foods may cause black stool during pregnancy, including:

Blueberries: These tiny fruits can turn your stool a darker color due to their deep blue pigment.
Licorice: Black licorice, specifically, can result in darker stools because of the strong artificial colors often used in this candy.
Iron-rich foods: Foods high in iron, such as spinach, red meat, and fortified cereals, can cause black stool.
Food coloring: Any foods using blue, black, or purple food coloring (think: richly-colored cupcakes) can temporarily darken the color of your stool.

A change in stool color that happens when you eat certain foods is generally harmless.

If you find that particular foods consistently change the color of your stool, keep a food journal and note correlations between your diet and your poop color.

Do changes in poop color related to food mean I’m not digesting food properly? No, food-related poop color changes don’t typically indicate a problem with digestion. The changes are often due to natural food pigments passing through your digestive system or the presence of unabsorbed substances, such as excess iron.

But if you’re experiencing other symptoms with a change in stool color, such as abdominal pain, bloating, or changes in stool consistency, consult your healthcare provider. These may indicate a digestive issue that may need attention.

3. Medications and supplements

During pregnancy, the medications you take can have an impact on the color of your stool.

These are the most common medications and supplements that can cause black poop (some of which are not recommended during pregnancy):

Iron supplements, including prenatal vitamins containing iron (to prevent anemia during pregnancy)
Bismuth (Pepto-Bismol, Bismatrol, Kaopectate, Kapectolin, Kola-Pectin, Diotame)
Aspirin
Ibuprofen
Iron salts
Anticoagulants (e.g., Warfarin)
Activated charcoal
Corticosteroids (e.g., Prednisolone, Hydrocortisone)
Heparin
Indomethacin
Levodopa (used to treat Parkinson’s disease)
Aluminum hydroxide (antacid)
Tetracycline (antibiotic)
Sulfonamides (a class of antibiotics)
Copper supplements
Methotrexate (used in cancer treatment and autoimmune diseases)

If you notice that your stool has turned black or very dark after taking a medication during pregnancy, it doesn’t necessarily mean something is wrong with the fetus. Dark stools are often a harmless side effect of certain medications, particularly those containing iron.

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4. Blood in stool

Internal bleeding in your upper digestive tract can result in a black or tarry appearance of your stool, a condition known as melena. This happens when blood is mixed and digested with your stool, altering its color.

The process of digestion changes the blood’s red color to a dark or black color, which is then reflected in your stool.

Bleeding in your digestive tract can also result in a change in stool consistency. The stool may become stickier and tarry due to the presence of digested blood.

Many health conditions may lead to internal bleeding and, subsequently, blood in the stool. These include:

Gastric ulcers: These are sores that develop on the lining of the stomach. Heavy drinkers, people who take a lot of NSAIDs, or those with an H. pylori infection are at the highest risk of bleeding ulcers.
Mallory-Weiss tear: This kind of tear is a laceration in the lining of the esophagus or stomach, typically caused by severe vomiting.
Esophageal varices: These are abnormally enlarged veins in the lower part of the esophagus that may rupture and bleed.
Hemorrhoids: Swollen blood vessels in the rectum or anus can bleed and cause changes in stool color.
Anal fissures: These are small tears in the lining of the anus.
Gastrointestinal bleeding: This can occur anywhere along the digestive tract, from the esophagus to the rectum.

The presence of blood in your stool may indicate a serious problem. It may be harmless in certain cases, like hemorrhoids or anal fissures, but it could also signal more serious conditions like gastric ulcers or esophageal varices.

If you notice black or tarry stools during your pregnancy, immediately consult your healthcare provider to identify the cause and, if necessary, begin appropriate treatment.

Is the baby okay?

Most changes in consistency or stool color during pregnancy are normal and do not necessarily indicate a problem with the fetus. Factors such as dietary changes, iron supplements, certain medications, and the normal hormonal shifts of pregnancy can all contribute to these changes.

However, there are some instances where changes in your bowel movements could potentially indicate an issue:

Black or tarry stools could signal internal bleeding, which may be a serious concern to you or your baby and should prompt immediate medical attention.
Persistent diarrhea can lead to dehydration, which can impact your well-being and potentially affect your baby.
Mucus in stool or pale-colored, yellowish stool may

Some symptoms that accompany darker stools may indicate a potential problem with the baby, such as:

Abdominal pain or cramping
Rectal bleeding
Persistent vomiting
Sudden weight loss
Elevated blood pressure

These symptoms can be a sign of preeclampsia, a pregnancy complication characterized by high blood pressure and signs of damage to another organ system, often the liver and kidneys.

It’s always best to consult your OB/GYN or primary healthcare provider if you notice any dramatic or persistent changes in your stool or other concerning symptoms. They can help determine whether these changes are just a normal part of pregnancy or something that needs further investigation.

Diagnosis

If you’re pregnant and experiencing changes in stool color to dark or black, your OB/GYN will undertake various steps to diagnose the cause. Once your gynecologist understands the reason behind the change, they can offer sound medical advice to help resolve it.

The first step in diagnosis often includes a detailed discussion about your dietary habits, medications, and overall health. This is to rule out benign causes like the intake of iron supplements, certain foods, or medications that can darken stool.

If your OB/GYN suspects a possible medical condition, they may suggest additional tests, like:

Stool test: A lab will analyze a sample of your stool to check for the presence of blood or infections that could be causing the color change.
Blood test: Blood tests can detect conditions such as anemia, which may be caused by internal bleeding, one of the serious conditions that can lead to black, tarry stools.
Endoscopy or colonoscopy: If the healthcare provider suspects a bleeding source in your gastrointestinal tract, they may recommend an endoscopy or colonoscopy. During these procedures, a thin tube with a light and camera is inserted into your throat (endoscopy) or colon (colonoscopy) to examine the esophagus, stomach, small intestine, and/or large intestine.

Your OB/GYN will manage the majority of typical pregnancy concerns. If your dark stool is caused by a gastrointestinal issue, you may be referred to a gastroenterologist for specialized care.

This doesn’t mean there’s a problem with your pregnancy, but rather that you might need expert attention for a specific health concern.

Treatment & prevention

The treatment for dark-colored stool during pregnancy largely depends on the identified cause. In many cases, treating the underlying cause is similar to ways you might also prevent dark stools during pregnancy.

Here are common treatments, home remedies, and prevention methods that may help stool from turning a dark color:

Dietary changes: If foods caused your black stool, dietary modifications can treat or prevent the issue. This could mean reducing the intake of foods like blueberries, black licorice, or other dark-colored foods, which can alter the color of your stool.
Changing or adjusting supplements/medications: If iron supplements or certain medications darken your poop, your doctor may suggest a different dosage or alternative medication. Always consult with your healthcare provider before making any changes to your medication regimen, particularly while you’re pregnant.
Increasing hydration and fiber intake: If constipation is identified as a contributing factor to your poop changes, consider increasing your water and fiber intake. Getting plenty of water and fiber can soften your stools and promote regular bowel movements. Foods rich in fiber include whole grains, fruits, vegetables, and legumes. For even better hydration, consider an electrolyte drink mix.
Infection treatment: If an infection is causing your dark stool, your doctor may prescribe appropriate medication to clear it up.
Treatment for underlying conditions: If your black stool is due to a more serious condition, such as gastrointestinal bleeding, you’ll need to receive treatment for that specific condition. This could involve a variety of treatments, from medication to, in severe cases, surgery.
Regular exercise: Regular, gentle exercise can help stimulate the digestive system and reduce the occurrence of constipation. Talk to your doctor about what type and amount of exercise is suitable for you during pregnancy.
Monitor bowel movements: Keep an eye on changes in your bowel movements so you detect any potential problems early. If you notice persistent black stools or any other concerning symptoms, don’t hesitate to contact your OB/GYN or other healthcare provider.

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When to call your doctor

While occasional black stool during pregnancy is usually not a cause for concern, certain symptoms alongside dark stools could indicate more serious issues.

These symptoms should prompt a call to your OB/GYN:

Persistent black stools: If your stool remains black or tarry over several bowel movements and is not linked to food or medication, this could indicate bleeding in the upper gastrointestinal tract. Consult with your doctor if you notice this persistent color change.
Pain or discomfort: Abdominal pain, discomfort, or cramping, especially when it’s severe or ongoing, could suggest a more serious condition. If this pain is accompanied by black stools, get in touch with your doctor.
Unexplained weight loss: If you’re experiencing unexpected weight loss along with changes in your bowel movements, seek medical advice.
Nausea or vomiting: Morning sickness is common in early pregnancy (throughout the first trimester). But persistent nausea or vomiting, especially when accompanied by changes in stool color, should be discussed with your healthcare provider.
Weakness, dizziness, or fainting: These symptoms could indicate anemia, possibly due to internal bleeding. Combined with black stool, these symptoms require immediate attention.

Emergency care should be sought if you experience any of the following alongside black stool:

Severe abdominal pain: If you have intense abdominal pain or discomfort, particularly focused in a specific area or that comes on suddenly, seek immediate medical attention.
Very bloody stools: Black stool may be harmless, but if it’s tarry in consistency or you notice a lot of bright red blood, this could be a sign of significant internal bleeding.
Signs of shock: Symptoms like cold, clammy skin, rapid heartbeat, shortness of breath, confusion, or loss of consciousness are signs of shock, which could be triggered by severe blood loss. This is a medical emergency and requires immediate attention.

Remember, when it comes to your health and your baby’s health during pregnancy, it’s always better to be safe than sorry. If you’re in doubt about any symptoms, it’s always a good idea to call your doctor.

Black Poop During Pregnancy: Normal, or Not?