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You thought morning sickness would end in the first trimester. So why are you experiencing third trimester nausea?

This annoying pregnancy symptom usually lets up after the first weeks of pregnancy. But for some, it can stick around or return in the last trimester.

In this article, we’re sharing 10 causes of nausea in the third trimester. We’ll also suggest remedies to help you feel better.

Nausea in Third Trimester Symptoms

During the later weeks of pregnancy, your first and second trimester symptoms are replaced by others. While every person is different, common third trimester symptoms include:

  • Heartburn
  • Shortness of breath
  • Swelling (ankles, fingers, face)
  • Tender breasts
  • Hemorrhoids
  • Sleeping problems
  • Signs of baby dropping

We often refer to nausea and vomiting as a first trimester pregnancy symptom when morning sickness is the worst. However, nausea can happen at any time during pregnancy and it’s still somewhat common in the third trimester.

According to one study, about 16% of women experienced nausea in the third trimester and about 7% experienced vomiting. Compared to other symptoms observed by researchers, nausea and vomiting were usually occasional and didn’t last for long periods of time.

What Causes Third Trimester Nausea?

In the first trimester, nausea and vomiting—called morning sickness—is extremely common. It’s often caused by changing hormones. Third trimester nausea has a different set of possible causes though.

Gas and Bloating

Gas and bloating are common during pregnancy. When your body produces more progesterone, it relaxes and slows down muscles involved in digestion. This can cause a variety of digestion issues, like gas and bloating. In more severe cases, gas can lead to nausea and other stomach issues. For some people, holding in gas (such as burps and flatulence) can cause abdominal pain, dizziness, and nausea.

If you think your third trimester nausea is caused by gas, you should contact your doctor. It’s a good idea to have it checked out since it could be a sign of a larger issue, like gastritis.


Another digestive-related issue that can cause third trimester nausea is constipation. When you’re constipated, your stool is difficult to push out normally. This causes a backup, stopping the new food in your stomach from moving through the intestines. When the food stays longer in the stomach, it can cause bloating and nausea.

There’s another reason why third trimester nausea may be connected to constipation. When stools stay inside the colon too long, it can change your gut bacteria, producing methane. Methane build-up can also cause nausea.

Acid Reflux

When most people think of acid reflux symptoms, heartburn comes to mind. However, it can also cause nausea. During pregnancy, acid reflux is very common. Changing hormones may be responsible—or it could be that your baby has grown and is pressing against your stomach.

This is particularly probable during the third trimester. As your baby gets bigger and bigger, she changes her position, adding more pressure.


Especially if you’re dealing with new food aversions and sensitivity during pregnancy, diet may be to blame for your third trimester nausea. For example, some people feel sick after eating a certain type of food. Common triggers include foods that are:

  • Spicy
  • Greasy
  • Acidic


Many times when adults get the flu, they experience cold-like symptoms, such as a runny nose rather than stomach problems. However, it’s still possible that your nausea could be caused by a viral illness like the flu. During pregnancy, you’re more susceptible to influenza and it’s more likely to cause severe symptoms. This is thanks to your changing immune system and changes to your lungs while expecting.

If your third trimester nausea is caused by the flu, make sure to keep an eye on your temperature. Fever may be associated with neural tube defects.

Food Poisoning

Nausea could be caused by another type of sickness: food poisoning. The symptoms of food poising vary by person but can include nausea and vomiting.

This explanation for nausea may be more likely during pregnancy. As your immune system is weaker, your body is more affected by bacteria, such as listeria. (This is why pregnant people are advised to avoid certain foods, like cold cut meats and pâté. Read: Listeria & Lunch Meat: Is It Safe?).

Prenatal Vitamins

Prenatal vitamins are necessary during pregnancy to ensure you’re getting all your essential nutrients—including folic acid. With that being said, sensitive stomachs might have a hard time adjusting to new vitamins. The iron contained in prenatal vitamins can set off your stomach, creating pain and nausea.

Consider your prenatal vitamin a possible cause of your third trimester nausea if:

  • You’ve experienced nausea since you’ve been taking your prenatal vitamins (during all trimesters)
  • You recently switched your prenatal vitamin brand and morning sickness returned


Hormones may still cause third trimester nausea. Changing hormones typically have the most impact in the first trimester, which is why morning sickness is one of the most common pregnancy symptoms. However, it’s possible that you’re still affected by hormones closer to your due date.


Nausea in the third trimester is often normal. In some cases though, it can be a sign of preeclampsia. Preeclampsia is a high blood pressure disorder that happens during pregnancy. It’s a serious condition that can lead to life-threatening complications if not monitored. Many people with preeclampsia do not experience symptoms. Those that do may have symptoms other than nausea, including:

  • Headaches
  • Vision problems
  • Upper right abdominal pain
  • Swelling
  • Shortness of breath

Liver Problems

Another less likely but serious cause of third trimester nausea is a liver problem. Liver disorders like HELLP syndrome can cause nausea. If your nausea doesn’t go away or is severe, it’s important to have it checked out by your doctor to rule out bigger problems.

Remedies for Third Trimester Nausea

When you’re dealing with third trimester nausea, the remedy depends on the cause. Use the list above to brainstorm possible causes and then try a remedy to alleviate the trigger of your nausea.

Treat Constipation

If you believe your nausea is caused by constipation, there’s a number of ways to help get things moving. Learn more by reading Constipation in Pregnancy: 7 Fixes.


If you’re experiencing bloating and gas that’s leading to nausea, here’s a few things you can try to help release gas:

  • Avoid trigger foods
  • Avoid carbonated drinks
  • Drink plenty of water
  • Get exercise daily (even a short walk or yoga session can help!)

Try Different Prenatal Vitamins

If you think that your nausea may be caused by the iron in your prenatal vitamins, you have a couple of choices.

  • Try another prenatal vitamin brand to see if it’s easier on your stomach
  • Get a prenatal vitamin without iron and choose a separate iron supplement (ex. some people better tolerate other forms of iron, like liquid iron)

Avoid Heartburn

Heartburn making you nauseous? Despite your best efforts, it can be hard to prevent this annoying pregnancy symptom. However, there’s a few things you can try to prevent heartburn:

  • Eat frequent small meals as opposed to 3 big meals
  • Make a conscious effort to eat slowly
  • Don’t lay down after eating
  • Stay away from trigger foods, like spicy, greasy, or acidic foods
  • Try drinking milk or eating yogurt to alleviate heartburn once it starts

Change Up Your Diet

If you notice that you feel nauseous after eating a certain food, do an experiment. Cut that food out for a few days and see if you feel any better. If you’re not sure of your food triggers, keep a diary where you log the foods you eat and your symptoms afterward. After a week, analyze your food diary and see if you can find a pattern.

Talk to Your Doctor

Although nausea in the third trimester is pretty common, if it’s severe, it could be a sign of a larger problem. It’s a good idea to get nausea problems checked out by your doctor, especially if it’s leading to vomiting.

If you believe your nausea is caused by an illness like food poisoning, you should ask your doctor for advice.

Summary: Nausea in Third Trimester

Nausea is most common in the first trimester when your hormones are rapidly changing. However, some people experience third trimester nausea too. Although hormones may be to blame, there’s several other potential causes. Reasons for third trimester nausea can include digestive problems, acid reflux, diet, illness, and reactions to prenatal vitamins. Although less likely, nausea can be a symptom of a more severe problem, like preeclampsia and liver problems.

To alleviate the feeling of sickness, you can try the remedies listed in this guide. However, it’s always best to report any changes in symptoms to your doctor. They can rule out serious conditions and help you find solutions that work.

Do You Have a Fetal Doppler Yet?

Fetal dopplers are at-home devices that allow you to listen to your baby while they’re still inside the womb. The small device is easy to use and only requires batteries and ultrasound gel (comes free with your device). Simply glide your probe across your baby belly until you find the heartbeat. The sound will be amplified through speakers to create a bonding experience for the entire family.

Connect with Your Baby Before Birth. Get a Fetal Doppler Today!

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