FAQ126, December 2018

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Morning Sickness: Nausea and Vomiting of Pregnancy

How common is nausea and vomiting of pregnancy?

Nausea and vomiting of pregnancy is a very common condition. Although nausea and vomiting of pregnancy often is called “morning sickness,” it can occur at any time of the day. Nausea and vomiting of pregnancy usually is not harmful to the fetus, but it can have a serious effect on your life, including your ability to work or do your normal daily activities.

When does nausea and vomiting of pregnancy start?

Nausea and vomiting of pregnancy usually starts before 9 weeks of pregnancy. For most women, it goes away by the second trimester (14 weeks of pregnancy). For some women, it lasts for several weeks or months. For a few women, it lasts throughout the entire pregnancy.

What is the difference between mild and severe nausea and vomiting of pregnancy?

Some women feel nauseated for a short time each day and may vomit once or twice. This usually is defined as mild nausea and vomiting of pregnancy. In more severe cases, nausea lasts several hours each day and vomiting occurs more frequently. Deciding to seek treatment depends on how much nausea and vomiting of pregnancy affects your life and causes you concern, not whether your condition is “mild” or “severe.”

What is hyperemesis gravidarum?

Hyperemesis gravidarum is the most severe form of nausea and vomiting of pregnancy. It occurs in up to 3% of pregnancies. This condition may be diagnosed when a woman has lost 5% of her prepregnancy weight and has other problems related to dehydration (loss of body fluids). Women with hyperemesis gravidarum need treatment to stop their vomiting and restore body fluids. Sometimes treatment in a hospital is needed.

Am I at risk of severe nausea and vomiting of pregnancy?

If you have any of the following factors, your risk of severe nausea and vomiting of pregnancy may be increased:

  • Being pregnant with more than one fetus (multiple pregnancy)
  • Past pregnancy with nausea and vomiting (either mild or severe)
  • Your mother or sister had severe nausea and vomiting of pregnancy
  • History of motion sickness or migraines
  • Being pregnant with a female fetus

Could nausea and vomiting during pregnancy be caused by another medical condition?

Some medical conditions can cause nausea and vomiting during pregnancy. These include an ulcer, food-related illness, thyroid disease, or gallbladder disease. Your obstetrician or other health care professional may suspect that you have one of these conditions if you have signs or symptoms that do not usually occur with nausea and vomiting of pregnancy:

  • Nausea and vomiting that occurs for the first time after 9 weeks of pregnancy
  • Abdominal pain or tenderness
  • Fever
  • Headache
  • Enlarged thyroid gland (swelling in the front of the neck)

Can nausea and vomiting of pregnancy affect my fetus?

Having nausea and vomiting of pregnancy usually does not harm your health or your fetus’s health. It does not mean your fetus is sick. It can become more of a problem if you cannot keep down any food or fluids and begin to lose weight. When this happens, it sometimes can affect the fetus’s weight at birth. You also can develop problems with your thyroid, liver, and fluid balance.

When is the best time to treat nausea and vomiting of pregnancy?

Because severe nausea and vomiting of pregnancy is hard to treat and can cause health problems, many experts recommend early treatment so that it does not become severe.

What can I do to feel better if I have nausea and vomiting of pregnancy?

Diet and lifestyle changes may help you feel better. You may need to try more than one of these suggestions:

  • Take a multivitamin.
  • Try eating dry toast or crackers in the morning before you get out of bed to avoid moving around on an empty stomach.
  • Drink fluids often.
  • Avoid smells that bother you.
  • Eat small, frequent meals instead of three large meals.
  • Try bland foods. For example, the “BRATT” diet (bananas, rice, applesauce, toast, and tea) is low in fat and easy to digest.
  • Try ginger ale made with real ginger, ginger tea made from fresh grated ginger, ginger capsules, and ginger candies.

If you do vomit a lot, it can cause some of your tooth enamel to wear away. This happens because your stomach contains a lot of acid. Rinsing your mouth with a teaspoon of baking soda dissolved in a cup of water may help neutralize the acid and protect your teeth.

Is there medical treatment for nausea and vomiting of pregnancy?

If diet and lifestyle changes do not help your symptoms, or if you have severe nausea and vomiting of pregnancy, medical treatment may be needed. If other medical conditions are ruled out, certain medications can be given to treat nausea and vomiting of pregnancy:

  • Vitamin B6 and doxylamine—Vitamin B6 is a safe, over-the-counter treatment that may be tried first. Doxylamine, a medication found in over-the-counter sleep aids, may be added if vitamin B6 alone does not relieve symptoms. A prescription drug that combines vitamin B6 and doxylamine is available. Both drugs—taken alone or together—have been found to be safe to take during pregnancy and have no harmful effects on the fetus.
  • “Antiemetic” drugs—If vitamin B6 and doxylamine do not work, “antiemetic” drugs may be prescribed. These drugs prevent vomiting. Many antiemetic drugs have been shown to be safe to use during pregnancy. Others have conflicting or limited safety information. You and your obstetrician or other members of your health care team can discuss all of these factors to determine the best treatment for your personal situation.

What may happen if my nausea and vomiting are severe or I have hyperemesis gravidarum?

You may need to stay in the hospital until your symptoms are under control. Lab tests may be done to check how your liver is working. If you are dehydrated from loss of fluids, you may receive fluids and vitamins through an intravenous line. If your vomiting cannot be controlled, you may need additional medication. If you continue to lose weight, sometimes tube feeding is recommended to ensure that you and your fetus are getting enough nutrients.


Dehydration: A condition that happens when the body does not have as much water as it needs.

Fetus: The stage of human development beyond 8 completed weeks after fertilization.

Hyperemesis Gravidarum: Severe nausea and vomiting during pregnancy that can lead to loss of weight and body fluids.

Nausea and Vomiting of Pregnancy: A condition that occurs in early pregnancy, usually starting before 9 weeks of pregnancy.

Nutrients: Nourishing substances found through food, such as vitamins and minerals.

Thyroid Gland: A butterfly-shaped gland located at the base of the neck in front of the windpipe. This gland makes, stores, and releases thyroid hormone that controls the body’s metabolism and regulates how parts of the body work.

If you have further questions, contact your obstetrician–gynecologist.

FAQ126: This information was designed as an educational aid to patients and sets forth current information and opinions related to women’s health. It is not intended as a statement of the standard of care, nor does it comprise all proper treatments or methods of care. It is not a substitute for a treating clinician’s independent professional judgment. Please check for updates at to ensure accuracy.

Copyright December 2018 by the American College of Obstetricians and Gynecologists

American College of Obstetricians and Gynecologists
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Mailing Address: PO Box 96920, Washington, DC 20024-9998