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. This information should not take the place of medical care and advice from your health care 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, and can occur at any time during the day and/or at night. These symptoms 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.

If the symptoms of NVP first start after 10 weeks of pregnancy, they may be due to other causes and should be assessed by your health care provider.

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. Women with HG usually 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 health care provider.

Is NVP harmful to my baby?

No, 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.

If I have severe NVP in my first pregnancy, will I have it again in future pregnancies?

About 75-85% of women who have had severe NVP or HG in their first pregnancy will also experience it in future pregnancies. There might be genetic factors that affect a woman’s chance of having NVP.

Are there effective treatments for NVP?

Yes. The combination of doxylamine succinate (an antihistamine) and pyridoxine (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. In the United States, it is sold under the name Diclegis®, and in Canada, it is sold under the name Diclectin®. A 2009 study showed that the use of Diclectin® during pregnancy did not have any long-term effects on babies’ brain development.

Are there other drugs that can be prescribed for NVP?

Yes, there are several other medications that can treat NVP. These can include chlorpromazine, dimenhydrinate, diphenhydramine, hydroxyzine, meclizine, metoclopramide, prochlorperazine, promethazine, and trimethobenzamide. Ondansetron and steroids can also be used.

The amount of information on the use of these medications in pregnancy and their side effects vary. You and your health care provider will decide the best treatment option for your symptoms.

Ondansetron and steroids can also be used, preferably to be given after 10 weeks of pregnancy. For ondansetron, monitoring with a test that checks the electrical activity of your heart (electrocardiography), and for constipation has been recommended.

Additionally, electrolyte imbalance is a risk factor for QT prolongation, and pregnant women with severe NVP or who have HG are at a greater risk of getting dehydrated, as many of them are not be able to maintain their hydration [as they need to be drinking at least 8 cups daily].

Are there any natural or alternative therapies to treat NVP?

Ginger and vitamin B6 (pyridoxine) are commonly used for the treatment of NVP. Several small studies show that up to 1000mg/day of ginger (dried ginger root powder equivalent) does not seem to increase risks to pregnancy and may be effective for NVP. The use of Vitamin B6, up to 200 mg/day (maximal daily dose), during pregnancy has been well studied, and thought to be effective for some women. Women taking other vitamin B6 containing products should ensure their entire vitamin B6 dose (from medications and/or multivitamins) does not exceed the maximal dose. This and all medication should be used under the care of your health care 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.

With every treatment, there are benefits and risks. It is important to talk with your health care provider before using any medications or treatments as they may interfere with other medication(s) or may be harmful during pregnancy.

How can I prepare myself for NVP?

Changes in food and lifestyle can help with NVP. For example, eating small meals every 1-2 hours, 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 and adding any type of protein source to each snack and each meal can help reduce the severity and frequency of symptoms. It is also helpful to treat NVP symptoms as soon as they occur. Also, prenatal vitamins may aggravate your NVP, as the iron may cause greater symptoms, upset stomach and/or constipation. Discuss with your healthcare provider for other options.

Discuss your NVP and any other symptoms with your health care provider, as there are other medical conditions that cause nausea and vomiting. For example, symptoms of heartburn, indigestion and/or acid reflux, such as burping, belching, nausea at night, burning, 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.

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.

Where can I get more information on my NVP treatment?

The Motherisk Program in Toronto, Canada (416-813-6780) is an affiliate of MotherToBaby (OTIS) and also offers a Diclegis® Surveillance Program Study Line (1-800-670-6126).

References Available By Request