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Patient education: Nausea and vomiting of pregnancy (Beyond the Basics)

Patient education: Nausea and vomiting of pregnancy (Beyond the Basics)
Authors:
Judith A Smith, PharmD, BCOP, CPHQ, FCCP, FHOPA, FISOPP
Karin A Fox, MD, MEd
Shannon M Clark, MD, MMS
Section Editor:
Charles J Lockwood, MD, MHCM
Deputy Editor:
Vanessa A Barss, MD, FACOG
Literature review current through: Nov 2022. | This topic last updated: Jul 01, 2021.

INTRODUCTION — Between 50 and 90 percent of women with normal pregnancies have some degree of nausea, with or without vomiting, in the first half of pregnancy. The duration and severity of symptoms varies among individuals.

This topic discusses ways to prevent and relieve nausea and vomiting, with and without medications. A more detailed article is available by subscription. (See "Nausea and vomiting of pregnancy: Clinical findings and evaluation" and "Nausea and vomiting of pregnancy: Treatment and outcome".)

MORNING SICKNESS VERSUS HYPEREMESIS

Morning sickness — "Morning sickness" is the term often used to describe mild nausea and vomiting due to pregnancy (and not due to an illness), even though symptoms may occur at any time of day and many women (80 percent) feel sick throughout the day or even at night.

Morning sickness often develops by five to six weeks of gestation. The symptoms are usually worst around nine weeks and typically improve by 16 to 18 weeks of gestation. However, symptoms continue into the third trimester in 15 to 20 percent of women and until delivery in 5 percent of women [1].

Of note, women with mild nausea and vomiting during pregnancy experience fewer miscarriages and stillbirths than women without these symptoms [2].

Hyperemesis gravidarum — Hyperemesis gravidarum is the term used to describe more severe nausea and vomiting of pregnancy. Women with hyperemesis often vomit multiple times every day, are often unable to consume food and liquids, and may lose more than 5 percent of their prepregnancy body weight. Women with hyperemesis gravidarum often become dehydrated and may develop vitamin and other nutrient deficiencies over time if they are not treated. This condition typically requires evaluation in the hospital and treatment with medication(s).

CAUSE OF NAUSEA AND VOMITING IN PREGNANCY — The cause of pregnancy-related nausea and vomiting is not clear. Several theories have been proposed, although none have been definitively proven. Various effects from increased hormone levels, a genetic predisposition, and psychological factors are among the more common theories.

RISK FACTORS — Some women are more likely to develop nausea and vomiting of pregnancy, including women who:

Developed these symptoms in a previous pregnancy

Experience nausea and vomiting while taking estrogen (for example, in birth control pills) or have menstrual migraines

Experience motion sickness

Have family members (especially sisters or mothers) who had these symptoms in pregnancy

Have a history of gastrointestinal problems (ie, reflux, ulcers)

Have twins, triplets, or other multiples

Have a molar pregnancy (a type of abnormal placenta and pregnancy)

WHEN TO SEEK HELP — Many women, especially those with mild to moderate nausea and/or vomiting, do not need medical treatment but should still let their obstetric care provider know if they are having symptoms. The clinician can then provide suggestions to help reduce symptoms or determine if treatment with a medication is advisable. (See 'Treatment of nausea and vomiting in pregnancy' below.)

Talk with your obstetric care provider right away if you have one or more of the following:

Signs of dehydration, including infrequent urination, dark-colored urine, or dizziness with standing

Vomiting repeatedly throughout the day, especially if you see any blood in the vomit

Abdominal or pelvic pain or cramping

Unable to keep down any food or drinks for more than 12 hours

Weight loss of more than 5 pounds (2.3 kg)

Fever or diarrhea in addition to nausea and vomiting

Feelings of hopelessness, wanting to end the pregnancy, or having suicidal thoughts because of the severity of nausea/vomiting symptoms

One or more tests may be recommended to determine a possible cause for and the severity of the nausea and vomiting. The tests may include blood tests, urine tests, or an ultrasound examination.

TREATMENT OF NAUSEA AND VOMITING IN PREGNANCY — Treatment can range from dietary and lifestyle changes to use of one of more medications. You may need to try several types of treatment or a combination of treatments over a period of weeks before finding what works best for you.

Treatment may not completely eliminate your nausea and vomiting. The goal is to make the symptoms tolerable so that you can eat and drink enough for appropriate fetal growth and have a reasonable quality of life. Fortunately, symptoms generally resolve by mid-pregnancy, whether or not you require any treatment. (See "Nausea and vomiting of pregnancy: Treatment and outcome".)

Dietary changes — Nausea and vomiting can be made worse from overeating or excessive hunger. Eating too much, avoiding food altogether, or not eating enough food may actually make nausea worse. Therefore:

Try eating before or as soon as you feel hungry to avoid an empty stomach.

Eat snacks frequently and have multiple small meals (eg, six small meals a day) that are high in protein or carbohydrates and low in fat.

Stick to a bland diet.

Drink cold, clear, and carbonated or sour fluids (eg, ginger ale, lemonade) and drink these in small amounts between meals.

Try smelling fresh lemon, mint, or orange or using an oil diffuser with these scents.

Avoid triggers — One of the most important treatments for pregnancy-related nausea and vomiting is to avoid odors, tastes, and other activities that trigger nausea. Eliminating food triggers, like spicy, sugary, and high fat foods, helps some women.

Other examples of triggers include:

Stuffy rooms

Odors (eg, perfume, chemicals, coffee, food, smoke)

Heat and humidity

Noise

Visual or physical motion (eg, flickering lights, driving)

Excessive exercise

Excessive salivation

Feeling tired

Other helpful tips — Other behaviors that may help prevent or relieve symptoms include:

Brushing your teeth after eating.

Staying well-hydrated.

Avoiding lying down immediately after eating and avoid quickly changing positions.

If you take a prenatal vitamin with iron and this worsens your symptoms, taking the vitamin at bedtime. If symptoms persist, stop the vitamins temporarily and let your obstetric care provider know that you stopped. The provider may suggest a chewable prenatal vitamin since some women tolerate this better than a vitamin in tablet form. If you stop taking your prenatal vitamin, the provider will suggest taking a supplement that contains 400 to 800 micrograms of folic acid until you are at least 14 weeks pregnant to reduce the risk of birth defects.

Complementary treatments — The following treatments may be useful when used with other treatments.

Acupuncture and acupressure – Acupressure wristbands (picture 1) and acupuncture have become a popular treatment for nausea and vomiting caused by pregnancy, motion sickness, and other causes. In some studies, these wristbands were no better than sham (fake, look-alike) wristbands [3]. However, some women do find them helpful and neither acupuncture nor acupressure have any known harmful side effects to mother or baby.

Ginger – Consuming ginger containing foods (eg, ginger lollipops, ginger ale) can be helpful managing mild nausea and vomiting. High doses of powdered ginger may help to relieve nausea and vomiting [4]; however, further studies are needed to confirm that high-dose powdered ginger is safe and effective.

Hypnosis and counseling – Hypnosis is helpful for some people. Counseling may be helpful for women with a history of anxiety or depression.

Treatments to avoid — Marijuana/THC-containing products (and similar products such as CBD oils) have not been shown to be safe in pregnancy and are not recommended for treatment of nausea and vomiting during pregnancy [5]. Long-term marijuana use and withdrawal from marijuana may increase vomiting. The long-term effects on the baby's developing brain are also unknown.

Fluids and nutrition — If you are unable to hold down food or liquids, you may be treated with intravenous (IV) fluids. This may be done in your doctor or nurse's office or in the hospital, depending upon the severity of your vomiting. For a short time, you may be advised not to eat or drink anything, to allow your stomach to rest. You can slowly begin to eat and drink again as you begin to feel better, usually within 24 to 48 hours.

If you continue to lose weight despite treatment with fluids and medications, your doctor may consider other forms of feeding, such as the use of a nasogastric tube (a tube that is inserted through your nose into the stomach) or supplemental nutrition through an IV line.

Medications — Medications that reduce nausea and vomiting are effective in some women. None of the medications discussed below are known to be harmful. Make sure you talk with your obstetric care provider before taking any new over-the-counter or prescription medications, including nutritional and herbal supplements.

Vitamin B6 and doxylamine – Over-the-counter vitamin B6 supplements can reduce symptoms of mild to moderate nausea but do not usually help with vomiting. Doxylamine is a medication that can reduce vomiting and may be combined with vitamin B6. Combinations of vitamin B6 and doxylamine formulations are available for the initial treatment of nausea (eg, Diclectin in Canada and Diclegis in the United States) and are available as a prescription. Doxylamine is also available in the United States in some over-the-counter nonprescription sleep aids (eg, Unisom, GoodSense Sleep Aid) and as a prescription antihistamine chewable tablet (Aldex AN).

Antihistamines – Antihistamines, such as diphenhydramine (Benadryl), can sometimes help relieve pregnancy-related nausea and vomiting. Drowsiness is a common side effect.

Anti-nausea medications that are available by prescription include:

Promethazine (Phenergan) – Promethazine is available in pill, oral solution, injectable, or rectal suppository form. It is usually taken every four to six hours and may cause drowsiness and dry mouth. Rare side effects include muscle contractions that cause twisting or jerking movements.

Metoclopramide (Reglan) – Metoclopramide speeds emptying of the stomach and may help to reduce nausea and vomiting. It is available in a pill, oral solution, and injectable form and is usually taken 30 minutes prior to meals and at bedtime. Metoclopramide can also be associated with twisting or jerking movements.

Ondansetron (Zofran) – Ondansetron is an anti-nausea medication that is usually taken by mouth or injection every 8 to 12 hours. Ondansetron should not be taken by patients with a condition called prolonged QT interval or with other medications that can prolong the QT interval, as this can lead to abnormally and potentially fatal, abnormal heart rhythm. Constipation is a side effect of ondansetron that some patients find bothersome and which can be treated with a stool softener and mild laxative.

Prochlorperazine (Compazine) – Prochlorperazine is available in a pill, rectal suppository, or injectable form. It may cause drowsiness and dry mouth. It can cause jerking motions (similar to promethazine and metoclopramide) and should be avoided in patients prone to QT prolongation (similar to ondansetron).

Corticosteroids (Solu-Cortef, dexamethasone) – A short course of steroid injections followed by a taper of pills may be offered to women who do not respond to a combination of the medications listed above.

PROGNOSIS AND OUTCOMES — Most women with pregnancy-related nausea and vomiting recover completely without any complications. Women with mild to moderate vomiting may gain less weight during early pregnancy. This is not harmful for the baby, except possibly if the mother was very underweight before pregnancy. Normal weight gain during pregnancy depends upon your prepregnancy height and weight. For women of normal weight (body mass index 18.5 to 24.9 kilogram/meter2), the recommended weight gain is between 25 and 35 pounds (11.5 to 16.0 kilograms) for a singleton pregnancy. However, most of this weight gain normally occurs in the last half of pregnancy, and pregnancy-associated nausea and vomiting has resolved by that time in most women.

In women with severe nausea and vomiting (hyperemesis gravidarum) who are hospitalized multiple times and who do not gain weight normally during pregnancy, there is a small chance that the baby will be underweight at birth.

RISK OF RECURRENCE — Women who have hyperemesis gravidarum in one pregnancy have a 15 to 20 percent risk of having it again in future pregnancies. Women who do not have severe nausea and vomiting in the first pregnancy are less likely to have it in future pregnancies [6].

WHERE TO GET MORE INFORMATION — Your obstetric care provider is the best source of information for questions and concerns related to your medical problem. This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for health care professionals, are also available. Some of the most relevant are listed below.

Patient level information — UpToDate offers two types of patient education materials.

The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.

Patient education: Morning sickness (The Basics)
Patient education: Pregnancy symptoms (The Basics)
Patient education: Taking over-the-counter medicines during pregnancy (The Basics)
Patient education: Motion sickness (The Basics)
Patient education: Hyperemesis gravidarum (The Basics)

Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.

Patient education: Should I have a screening test for Down syndrome during pregnancy? (Beyond the Basics)

Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.

Approach to the adult with nausea and vomiting
Characteristics of antiemetic drugs
Nausea and vomiting of pregnancy: Clinical findings and evaluation
Nausea and vomiting of pregnancy: Treatment and outcome

The following organizations also provide reliable health information.

National Library of Medicine

     (www.nlm.nih.gov/medlineplus/ency/article/001499.htm, available in Spanish)

Society of Obstetricians and Gynecologists of Canada

     (www.sogc.org)

Organization of Teratology Information Specialists

(www.mothertobaby.org/fact-sheets-parent/)

[1,3,6-9]

ACKNOWLEDGMENT — The editorial staff at UpToDate would like to acknowledge Susan Ramin, MD, and Jerrie S Refuerzo, MD, who contributed to an earlier version of this topic review.

This generalized information is a limited summary of diagnosis, treatment, and/or medication information. It is not meant to be comprehensive and should be used as a tool to help the user understand and/or assess potential diagnostic and treatment options. It does NOT include all information about conditions, treatments, medications, side effects, or risks that may apply to a specific patient. It is not intended to be medical advice or a substitute for the medical advice, diagnosis, or treatment of a health care provider based on the health care provider's examination and assessment of a patient's specific and unique circumstances. Patients must speak with a health care provider for complete information about their health, medical questions, and treatment options, including any risks or benefits regarding use of medications. This information does not endorse any treatments or medications as safe, effective, or approved for treating a specific patient. UpToDate, Inc. and its affiliates disclaim any warranty or liability relating to this information or the use thereof. The use of this information is governed by the Terms of Use, available at https://www.wolterskluwer.com/en/know/clinical-effectiveness-terms ©2023 UpToDate, Inc. and its affiliates and/or licensors. All rights reserved.
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