7 Reasons For Third Trimester Nausea And Its Prevention

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Third-trimester nausea and vomiting are less common. Usually, nausea and vomiting subside by the 16th week of pregnancy in most women. Overall, only 20% of pregnant women experience nausea and vomiting throughout pregnancy (1).

The exact causes of nausea and vomiting in pregnancy are unknown, but knowing and avoiding triggers can help you manage the condition. Occasional incidence of nausea and vomiting in the third trimester may not be a cause for concern. However, seek medical care if you have persistent nausea or vomiting in the third trimester.

Read on to know about the common causes and preventive measures for third-trimester nausea and vomiting.

In This Article

Causes Of Third Trimester Nausea

According to Greg J. Marchand, MD, FACS, FACOG, program director at Steward Health, Providence, Rhode Island, “Acid reflux and stomach bugs (stomach viruses and stomach flu) are common in pregnant women in the third trimester. However, nausea that lasts the whole pregnancy is rare.”

While increasing HCG levels are one of the reasons for the first trimester morning sickness, it can be difficult to understand the cause of nausea in the third trimester (2). The following could be the possible causes of nausea in the third trimester.

  1. Changing hormones: Frequent fluctuations in the hormones might cause nausea and vomiting in the third trimester. Pregnancy-related hormonal changes can also slow down the movement of the stomach, prolonging the time it takes for food to empty out and increasing the risk of gastroesophageal reflux disease (GERD). According to a recent study, GERD is linked to heightened severity of nausea and vomiting during pregnancy (NVP) (3)
  2. Growing baby: The growing baby exerts a lot of pressure on the digestive system. With decreasing space in the abdomen as the baby grows, you may experience pregnancy discomfort, including nausea, heartburn, and vomiting.

    Pressure on the digestive system may cause nausea

    Image: IStock

  3. Diet: Too spicy, greasy, or acidic foods can exacerbate nausea and vomiting. Track your pregnancy nutrition and avoid foods that cause or increase your queasiness.
  4. Changes in the body: Growing uterus and baby can make you feel ill at times. Pressure from the growing uterus, sleep disturbances, stress, and anxiety about labor, childcare, etc., may cause aggravated, uncomfortable pregnancy symptoms, including nausea and vomiting.
  5. Preeclampsia: The sudden reappearance of nausea and vomiting midway through pregnancy may be associated with hypertension and preeclampsia. Inform your healthcare provider about any concerning symptoms (4). According to the American Heart Association (AHA), preeclampsia affects 5 to 7% of pregnant women globally and accounts for 70,000 maternal and 500,000 fetal mortalities annually. In the US, preeclampsia is a prominent cause of maternal mortality, severe morbidity, ICU admissions, cesarean deliveries, and premature births.

    Preeclampsia may cause third trimester nausea

    Image: IStock

  6. HELLP syndrome: HELLP syndrome stands for the following blood and liver problems (5).
  • H – Hemolysis (It is the breakdown of the red blood cells)
  • EL – Elevated liver enzymes (It can be a sign of liver problems)
  • LP – Low platelet count (It can lead to serious bleeding)

Nausea and throwing up (that gets worse) are the common symptoms of HELLP syndrome.

Dr. Marchand adds, “Apart from stomach illnesses, worsening acid reflux, or nausea that has never subsided, you should not have a new onset of nausea in the third trimester. If you have a new onset of nausea that is not explained by one of the previously listed conditions, it could be a sign of pregnancy complications, such as HELLP syndrome.”

  1. Acute fatty liver of pregnancy: Acute fatty liver of pregnancy (AFLP) is a rare but serious problem. The exact cause of AFLP is unknown.  However, it starts late in the third trimester of pregnancy and can cause nausea and vomiting (6).
protip_icon Did you know?
Prenatal vitamins, especially those containing iron, can also cause nausea in later pregnancy (2).
It is rare condition that may cause nausea and vomiting

Image: IStock

Ways To Prevent Nausea In The Third Trimester

The following measures can help in preventing nausea (7).

  • Try to get enough sleep and rest.
  • Avoid caffeinated beverages, including tea, and coffee as they aggravate your symptoms.
  • Eat small, frequent meals throughout the day.
  • Consume a lot of fluids to avoid dehydration and associated nausea.
  • Practice gentle exercises after consulting your healthcare provider.

    Practice gentle exercises after consulting your Ob-GYN

    Image: Shutterstock

  • Avoid lying down immediately after meals and have your dinner two to three hours before bedtime.
  • Sugary, spicy, and greasy foods can worsen the nausea symptoms. Identify which food triggers your symptoms to avoid them.
  • Some fragrances or smells can trigger your nausea, so avoid them.
  • Eating bland food when you are nauseated might help. You can include rusk, Jell-O, popsicles, chicken broth, saltine crackers, gelatin desserts, pretzels, etc.
  • Ginger shows varying effectiveness in different women with nausea and vomiting of pregnancy (1).

    Ginger may help reduce third trimester nausea

    Image: Shutterstock

  • Stay in well-ventilated and lighted places as closed spaces may also aggravate nausea and vomiting in pregnancy.

If nausea and vomiting are too severe, contact your healthcare provider. They might prescribe the necessary medications to help you feel better.

protip_icon Quick tip
If you can’t keep fluids down, freeze them. Consuming frozen fluids numbs the back of your mouth and removes the bad taste and sensation that brings nausea (2).

Signs You Need To See A Doctor

While nausea and vomiting of pregnancy are not always a sign of a problem, you should see your doctor in the following scenarios.

  • Inability to keep any food or fluids down
  • Loss of appetite
  • Sudden weight loss
  • Reduction in the fetal movement
  • Severe weakness
  • Dizziness
  • Several episodes of vomiting throughout the day

Frequently Asked Questions

1. Can I take medication for nausea in the third trimester?

According to the US Food and Drug Association (FDA), a combination of doxylamine succinate and pyridoxine hydrochloride tablet (trade name Diclegis) can manage nausea and vomiting in pregnancy (8)

Some antihistamines, ondansetron, phenothiazines, metoclopramide, and corticosteroids can also treat nausea and vomiting in pregnancy (1). However, do not use any medicine without your doctor’s consent.

2. Can third-trimester nausea be a sign of labor?

While nausea is not a conclusive sign of labor, sudden and persistent nausea in the third trimester can indicate premature labor (9).

3. Is nausea in the third trimester normal?

Nausea in the third trimester is not common. However, it does not always happen due to an underlying pathology. Nausea in the third trimester does not indicate any harm to the mother or fetus, but communication with professionals is necessary since they will be able to handle the condition better.

4. Does nausea while pregnant affect the baby in the third trimester?

Nausea or vomiting do not directly affect the baby but can cause discomfort for the expectant mother. Mild vomiting may not cause any impacts on the mother and the baby. However, excessive vomiting can lead to dehydration, and dehydration can affect the baby.

5. How long can I go without eating while pregnant to avoid nausea?

Nausea may occur or worsen if you go too long without eating during pregnancy. It is recommended to eat every two hours if you experience nausea during pregnancy. Avoid consuming high-fat or greasy foods that are difficult to digest (10).

6. What drinks help with pregnancy nausea?

Some women may find relief in drinking carbonated beverages such as sodas, milk, or tea. Drinking peppermint or spearmint tea can also help reduce nausea and vomiting in some women. Chamomile and ginger tea can also help relieve nausea (10).

Nausea is a common occurrence during the initial weeks of pregnancy. However, third-trimester nausea is not a common symptom and should be reported to the doctor at once. If left unattended, nausea during the third trimester might lead to dehydration and also increase the chances of complications for the baby and the mother. Treatment of such severe cases of nausea might require hospitalization and the administration of intravenous fluids. Thus, it is advised that pregnant women should stay hydrated, avoid spicy or oily food and get enough rest and sleep to avoid the symptoms of nausea.

Infographic: How Can You Avoid Nausea During the Third Trimester

Just when you were happy that your morning sickness had subsided in your second trimester, it might have bounced back as soon as your third trimester began. The good news is that you can prevent nausea in your third trimester. The infographic below offers tips on controlling or suppressing nausea toward the end of your pregnancy.

ways to prevent during the third trimester (infographic)

Illustration: Momjunction Design Team

Get high-quality PDF version by clicking below.

Download Infographic in PDF version Download Infographic
Download Infographic in PDF version

Key Pointers

  • Nausea in the third trimester could be due to the growing baby’s increased strain on your digestive system.
  • Preeclampsia, HELLP syndrome, and AFLP can also cause nausea in the third trimester.
  • Eating small frequent meals, getting enough rest, and doing some light exercises can help prevent nausea.
  • Nausea in the third trimester is uncommon but generally does not indicate any harm to the mother and fetus.

If you’re pregnant and feeling nausea, learn how to manage vomiting during the third trimester. Learn how to reduce and cope with this bothersome symptom.


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