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Why are you running to the bathroom so much during late pregnancy?

Although diarrhea can happen at any time while you’re expecting, it’s especially common in the third trimester. It can even be a sign that labor is on its way.

But what causes it? And can you do anything to make it better?

In this guide, you’ll learn why third-trimester diarrhea happens and when you should talk to your doctor.

Diarrhea During Pregnancy

Diarrhea is when your stools are loose and watery. It can also cause you to use the bathroom more frequently or urgently.

Diarrhea is common and can be caused by an infection, virus, food allergy, or other health causes. It can be more common during pregnancy for other reasons, like changing hormones and diet changes. In fact, one-third of pregnant women experience constipation and diarrhea, according to research.

Some people experience diarrhea early on or in the middle of their pregnancy. However, diarrhea during pregnancy is most common during the third trimester as your body prepares for birth.

It can last a day, a few days, or a few weeks. Diarrhea is usually harmless and isn’t a cause for concern unless you become dehydrated.

Symptoms of diarrhea include:

  • Loose stools
  • Inability to control bowels (leaking stools)
  • Urgency to use the bathroom
  • Cramps or stomach pain
  • Bloating

Diarrhea can also cause other side effects. If you experience any of the following, you should seek medical attention:

  • Bloody stools
  • Dehydration
  • Fever

First Trimester: Is Diarrhea a Pregnancy Symptom?

Some people wonder if diarrhea is a sign they’re pregnant. Diarrhea isn’t a typical pregnancy sign. However, some people may notice digestion changes—like diarrhea—in the first trimester as their body adjusts.

The hormone progesterone rises during early pregnancy. This relaxes your muscles, including your intestines. This slows down your digestion, which may cause constipation. However, instead of getting constipated, the hormone can cause some people to have diarrhea instead.

So while it’s possible to have diarrhea during early pregnancy, it shouldn’t be considered a sign you’re pregnant.

Third Trimester Diarrhea

Most people who have pregnancy diarrhea experience it in the third trimester. It’s usually normal and can be a sign that labor is nearing. That’s because the hormone that gets your body ready for labor can also cause diarrhea.

After a bout of diarrhea, some people go into labor right after. For others, it’s a sign that labor is coming but is still weeks away.

Keep in mind that diarrhea isn’t always a sign that labor will start soon, so don’t panic if it doesn’t. If you’re unsure whether labor is near, look out for labor signs, like bloody show. To learn more, read 6 Near Labor Signs & How to Know When to Go to Hospital.

Third Trimester Diarrhea Causes

Third Trimester diarrhea is common thanks to hormones nearing the end of pregnancy. However, routine causes, like a virus, could also be to blame.

If you’re unsure of the cause and it lasts more than a few days, talk to your doctor.


The most common cause of third-trimester diarrhea is the release of prostaglandins.

Prostaglandins are hormones that make your uterus contract and soften your cervix to prepare it for labor. Unfortunately, it can also soften stools, sometimes causing loose stools and diarrhea.

Thanks to this hormone, many people get a bad case of diarrhea before labor.

Diet Changes

If you’ve recently changed your diet, it could be the cause of your diarrhea. This is more common during the first trimester when pregnancy cravings may cause you to try new foods. However, it can happen at any time you alter your diet. For example, if you’re eating more dairy products, the increase in lactose can cause diarrhea.

Medication or Prenatal Vitamins

Certain medications and prenatal vitamins can also impact your digestion. While your prenatal vitamins might not have bothered you in the beginning, they might seem to make diarrhea worse in the third trimester as your hormones change. Some people find that iron supplements specifically can cause stomach disturbances.

If you think your prenatal vitamin is worsening your diarrhea, talk to your doctor about taking another brand.


Diarrhea can also be caused by a virus, like the flu.

If you’re not sure if your diarrhea is caused by a virus, talk to your doctor. While they can determine if you’re sick, antibiotics won’t help with the sickness or diarrhea. In this case, you’ll likely need to wait for the virus to clear before your diarrhea gets better.

Bacteria or Food Poisoning

Diarrhea can be caused by bacteria or food poisoning, like listeria or salmonella. During pregnancy, your immune system is weaker and you’re more at risk for food poisoning. The consequences of food poisoning could also be more severe, possibly affecting your baby.

If you suspect food poisoning, seek medical care. In cases of a bacterial infection, your doctor will likely prescribe a course of antibiotics.


If you’re traveling in the third trimester, you may experience “traveler’s diarrhea.” This usually happens when a beverage or food you consume is contaminated with fecal matter. During pregnancy, you may be more likely to become dehydrated due to diarrhea when traveling.

When traveling while pregnant, take extra precaution to avoid diarrhea by:

  • Drinking bottled water only
  • Avoiding tap water
  • Avoiding street vendors
  • Don’t eat fruits that come unpeeled

Dealing with Third Trimester Diarrhea

If your third-trimester diarrhea is caused by pregnancy hormones and chemicals, you’ll have to let it run its course. Unless your diarrhea is caused by a virus or bacteria, treatment is usually unnecessary.

There are some things you should do to lessen the impact of diarrhea and make it easier on your body.

Stay Hydrated

Although it’s usually harmless, one concern with third-trimester diarrhea is dehydration. If you’re constantly using the washroom, your fluids can become depleted. This can cause dehydration, which can lead to other issues, like constipation and pregnancy complications.

To stay hydrated, make sure to drink plenty of fluids, especially if you have third-trimester diarrhea. Consider topping up your fluid levels with:

  • Water
  • Broths
  • Soups
  • Pregnancy-safe herbal teas

Avoid Dehydrating Beverages

Drinking dehydrating beverages can make it difficult to keep hydrated. Avoid these drinks, especially when you have diarrhea:

  • Coffee
  • Caffeinated tea
  • Energy drinks

Avoid Diarrhea-Causing Foods

When diarrhea is bad, consider staying away from foods that can make it worse, including:

  • Spicy foods
  • Fried foods
  • Fatty foods
  • Dairy products

Eat Foods to Bulk Up Your Stools

When you have third-trimester diarrhea, you might be able to limit your bathroom trips by eating foods to bulk up your stool. The foods below will help your stool stay solid:

  • Oatmeal
  • Bananas
  • Carrots
  • Peas
  • Beans
  • Apples

Wait It Out

In most cases, diarrhea will clear up in a few days without any treatment. Although annoying, remember that it’s only temporary and may be a sign your body is getting ready to give birth.

During pregnancy, avoid taking over-the-counter antidiarrheal medication unless it’s recommended by your doctor.

Talk to Your Doctor

In cases where diarrhea is severe and doesn’t stop after a few days, talk to your doctor. They may check whether your diarrhea is caused by a virus or bacteria.

You should also talk to your doctor if you’re having trouble staying hydrated. In cases of extreme diarrhea and dehydration, a doctor may recommend IV fluids.

Keep an eye out for red flags, like blood or mucus in your stool. Fever can also be a sign of infection. If anything unusual accompanies your diarrhea, seek medical attention.

Summary: Third Trimester Diarrhea

Diarrhea can happen anytime during pregnancy but is most common during the third trimester. That’s because hormones to get your body ready for labor also cause changes to your digestion. This can result in loose, watery stools. Although annoying, diarrhea during the third trimester is usually harmless and will go away after a few days. The most important thing to remember is to stay hydrated to replace the fluids you lose.

In some cases, third-trimester diarrhea is caused by a virus, bacteria, or another health condition. Diarrhea that doesn’t go away or is accompanied by a fever or blood or mucus in the stool is not normal. Seek medical attention if this happens.

P.S. Do You Have a Fetal Doppler Yet?

Fetal Dopplers are handheld devices that you can use to hear your baby’s heartbeat. Similar to an ultrasound, a probe detects your baby and the heartbeat is amplified through speakers. Many parents say hearing a heartbeat helps them connect with the baby before birth. It’s a magical experience in the weeks leading up to labor and can provide comfort for anxious parents.

Bond with Baby Before Labor. Try a Fetal Doppler Today!

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