In every pregnancy, a woman starts out with a 3-5% chance of having a baby with a birth defect. This is called her background risk. This sheet talks about nausea and vomiting during pregnancy (NVP). This information should not take the place of medical care and advice from your healthcare provider.

What is nausea and vomiting of pregnancy (NVP)?

NVP or “morning sickness” is the most common medical condition in pregnancy. It affects 50-80% of pregnant women. NVP symptoms can range from mild to severe. The symptoms can happen at any time during the day or at night. Symptoms can include nausea, dry heaves, retching and/or vomiting. NVP usually begins between 4-9 weeks of pregnancy, and peaks between 7-12 weeks. In most women, symptoms go away between 12-16 weeks of pregnancy. Up to 15% of women will continue to have symptoms up to 20 weeks of pregnancy or until delivery.

The most severe form of NVP is known as hyperemesis gravidarum (HG), which affects up to 3% of pregnant women. HG is when there is severe nausea and constant vomiting that causes weight loss and dehydration (not getting enough water). Women with HG can require hospitalization.

Whether symptoms of NVP are mild, moderate or severe, it can have a major impact on a woman’s quality of life. If NVP is affecting your ability to eat, sleep and perform your daily activities, speak with your healthcare provider.

If the symptoms of NVP first start at the 10th week of pregnancy or later they may be due to other causes and should be discussed with your healthcare provider.

Is NVP harmful to my baby?

NVP is not usually harmful to your baby. In fact, NVP may have a protective effect on the baby. Studies have suggested that women with NVP may have fewer miscarriages, as well as babies with fewer birth defects and higher IQs.

Pregnant women with severe NVP or who have HG are at a greater risk of getting dehydrated, as many of them are not able to drink enough water. This can cause medical complications for the mother. Some studies have found that HG might be associated with a slightly higher chance to have a baby that is smaller than expected.

Are there effective treatments for NVP?

Yes there are a number of treatments that may help pregnant women. No one therapy will help 100% of the women and a combination of therapies may be needed by some pregnant women.

The combination of doxylamine succinate (an antihistamine) and pyridoxine hydrochloride (vitamin B6) has been shown to be an effective NVP treatment. It is recommended as a first-line treatment by the American Congress of Obstetricians and Gynecologists (ACOG), and several medical organizations in Canada. MotherToBaby has a fact sheet on doxylamine succinate and pyridoxine hydrochloride at https://mothertobaby.org/fact-sheets/doxylamine-succinate-pyridoxine-hydrochloride-diclegisdiclectin-pregnancy/pdf/.

There are several other prescription medications that have been used to treat NVP. The amount of information on the use of these medications in pregnancy and their side effects vary. You and your healthcare provider will decide the best treatment options for your symptoms.

Ginger and vitamin B6 (pyridoxine) have also been used for NVP. Several small studies show that up to 1000mg/day (1gram) of ginger (dried or fresh ginger root) does not seem to increase risks to pregnancy and may be effective for NVP. MotherToBaby has a fact sheet on ginger https://mothertobaby.org/fact-sheets/ginger-pregnancy/pdf/.

The use of Vitamin B6, up to 200 mg/day, during pregnancy has been well studied, and thought to be helpful for some women. Women taking other vitamin B6 containing products should ensure their entire vitamin B6 dose (from medications and/or multivitamins) is not higher than the maximum dose of 200 mg per day. These supplements should only be used after discussing their use with your healthcare provider.

Acupuncture or acupressure (which stimulates a point on the inside of the wrist with pressure, needle or mild electrical current) and hypnosis have been shown to have mixed results for treating symptoms of NVP. As with any treatment, it is important to discuss benefits and any potential risks with your healthcare provider.

Are there other lifestyle changes that I can try to help with my NVP?

Changes in food and lifestyle can help with NVP. Tips that have helped other women to lessen NVP symptoms and /or have NVP symptoms happen less often include:

  • eating small meals or a snack every 1-2 hours,
  • add a protein source to each snack and each meal
  • drinking cold or partially frozen fluids daily (8 cups),
  • keep solids and liquids separate, by drinking 20 to 30 minutes before or after meals/snacks.

It is also helpful to treat NVP symptoms as soon as they occur, as it may be easier to get them under control if treatment or lifestyle changes are started right away.

Prenatal vitamins may trigger NVP, as the iron may cause greater symptoms, upset stomach and/or constipation. Discuss this with your healthcare provider if you are having trouble taking your prenatal vitamin.

Could my nausea and/or vomiting be due to something other than pregnancy?

Discuss your NVP and any other symptoms with your healthcare providers, as there are other medical conditions that cause nausea and vomiting. For example, symptoms of heartburn, indigestion and/or acid reflux (such as burning, burping, belching, or nausea at night) affect 40-85% of pregnant women, and over 50% of symptoms will appear during the first trimester. Some women find relief when avoiding fatty/acidic foods, and when elevating the head of the bed to sleep on an incline (to raise the head higher than the abdomen).

Another example, a bacterial infection called Helicobacter pylori, has been associated with HG. Testing for this bacterium is recommended for women with a history of severe NVP or HG. If a woman is positive for this bacterium, she can be treated during her pregnancy. Your health care provider can help to determine if there are other possible medical causes for your NVP symptoms

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