11611 Health Library | Health and Wellness | Wellmont Health System
  • Hyperemesis Gravidarum

    (Severe Morning Sickness; Persistent Vomiting of Pregnancy; HG)


    Hyperemesis gravidarum (HG) is an uncommon condition characterized by frequent, persistent, and severe vomiting and nausea during pregnancy. As a result, you may be unable to take in a sufficient amount of food and fluids. It can cause a weight loss of more than 5% of your pre-pregnancy body weight. This can also cause dehydration and vitamin and mineral deficiencies. Treatment may require hospitalization.
    HG is a more severe form of nausea and vomiting of pregnancy (NVP), also called morning sickness. Morning sickness affects anywhere between 50% to 90% of pregnant women. HG is estimated to occur in 0.5%-2% of pregnancies.


    There are many theories about the causes of HG, but none have been confirmed. HG is a complex disease that is likely caused by many factors. Some of these include:
    • Vitamin B deficiency
    • Human chorionic gonadotropin (hyperemesis most severe during period of highest HCG levels)
    • Hyperthyroidism (may be a result of high chorionic gonadotropin levels)
    • Endocrine imbalances (high levels of estrogen)
    • A multiple pregnancy (twins or more)
    • Brain nausea-control-center sensitivity to pregnancy changes
    The Brain May Be Cause of Nausea
    Brainstem and brain
    Copyright © Nucleus Medical Media, Inc.

    Risk Factors

    Some researchers have found that the following factors increase your chance of developing HG. If you have any of these risk factors, tell your doctor:
    • History of HG in previous pregnancies
    • Molar pregnancy (an abnormal mass made up of placental tissue; may or may not contain some fetal tissue)
    • Mother or sister with HG
    • A multiple pregnancy
    • Young maternal age
    • No previous completed pregnancies
    • First-time pregnancy
    • Obesity


    The following list of symptoms are general and may be caused by other, less serious health conditions. However, if you experience any one of them, call your physician to discuss your condition. Symptoms may include:
    • Severe and persistent vomiting, beginning 4 to 6 weeks after conception, peaking 9-13 weeks, and usually improving and ending 14-20 weeks
    • Progressive weight loss of greater than 5% of original, pre-pregnancy body weight
    • Dehydration, which may show the following signs:
      • Ketones in urine
      • Increased hematocrit (% of red blood cells in blood)
      • Increased pulse rate
      • Decreased blood pressure
    • Rapid heartbeat (tachycardia)
    • Excessive salivation (ptyalism)
    • Distinctive breath odor (ketonic odor)


    Your doctor will ask about your symptoms and medical history. A physical exam will be done. Tests may include the following:
    • Weight measurement—to determine if you have lost weight
    • Blood electrolytes—to identify disturbances in salts and other minerals in the blood due to extreme vomiting
    • Ketones—to determine if you are dehydrated
    • Overall condition—ability to perform daily activities; psychological state of mind


    Treating HG symptoms early in pregnancy can make you less sick in the long run and can decrease recovery time. Because HG is caused by many factors that vary among women, it is difficult to find a treatment that works for everyone. Talk with your doctor about the best treatment plan for you. Treatment options include the following:


    Try to eat frequent, small meals, bland or dry foods, high-protein choices.

    Anti-nausea Medications

    Reducing nausea, and thus allowing eating and drinking, will hasten recovery. Due to the risk of stating that a drug is safe for use during pregnancy, very few pharmaceutical manufacturers will say that their drugs are intended for a pregnancy condition like HG (examples: promethazine or prochlorperazine). However, doctors often recommend that women with HG take certain anti-nausea medicines, balancing the potential benefits and risks. Talk to your doctor about the right medicines for you.
    A common and safe remedy is to take supplemental vitamin B6 (pyridoxine), to a maximum of 100 mg/day. The American Congress of Obstetricians and Gynecologists recommends that first-line treatment of nausea and vomiting of pregnancy should start with pyridoxine with or without doxylamine. Pyridoxine has been found to be effective in significantly reducing severe vomiting.

    IV Hydration and Anti-nausea Medications

    In urgent visit situations, HG can be managed by IV fluids and vitamins. This can sometimes be done without hospitalization. Very rarely, some people require IV fluids throughout the entire pregnancy.

    Nutrition by Vein

    If you are unable to tolerate food by mouth, you may need to receive nutrition by vein. This is called parenteral nutrition. A special kind of catheter is placed in a large vein and liquid nutrition is given. This can sometimes be done without hospitalization.

    Alternative Therapy

    Acupressure may help to reduce nausea. Acupressure is when pressure is applied to acupuncture points.

    Termination of Pregnancy

    In extreme cases, induced abortion may be considered.
    If you are diagnosed with HG, follow your doctor's instructions.
    If you are diagnosed with HG, follow your doctor's instructions.


    Many of the conditions that lead to HG are not preventable. It is unknown why some women without those conditions develop HG. You can try to reduce your nausea during pregnancy by:
    • Avoiding smells, foods, or other things that stimulate nausea
    • Eating frequent small meals
    • Not allowing yourself to get too hungry or too full


    The American Congress of Obstetricians and Gynecologists http://www.acog.org

    Hyperemesis Education and Research Foundation http://www.helpher.org

    National Organization for Rare Diseases http://www.rarediseases.org


    The Canadian Women's Health Network http://www.cwhn.ca/en

    The Society of Obstetricians and Gynaecologists of Canada (SOGC) http://www.sogc.org/index%5Fe.asp


    ACOG issues guidance on the treatment of morning sickness during pregnancy. American College of Obstetrics and Gynecology website. Available at: http://www.acog.org/About%5FACOG/News%5FRoom/News%5FReleases/2004/ACOG%5FIssues%5FGuidance%5Fon%5FTreatment%5Fof%5FMorning%5FSickness%5FDuring%5FPregnancy. Accessed August 20, 2011.

    Acupuncture. EBSCO Natural and Alternative Treatments website. Available at: http://www.ebscohost.com/healthLibrary. Updated January 2009. Accessed January 19, 2009.

    Beers MH, Berkow R, eds. The Merck Manual of Diagnosis and Therapy. 17th ed. Whitehouse Station, NJ: Merck Research Laboratories; 1999.

    Burrow GN, Duffy TP, eds. Medical Complications During Pregnancy. 5th ed. Philadelphia, PA: WB Saunders Company; 1999.

    Cunningham FG, Gilstrap LC, Gant NF, Hauth JC, Leveno KJ, Wenstrom KD, eds. Williams Obstetrics. 21st ed. New York, NY: McGraw-Hill; 2001.

    Ferri, Fred, ed. Ferri’s Clinical Advisor 2010. 1st ed. Philadelphia: Mosby Elsevier, 2009.

    Gabbe SG, Niebyl JR, Simpson JL. Obstetrics: Normal and Problem Pregnancies. 5th ed. United Kingdom: Churchill Livingstone; 2007.

    Gastroenterology Clinics of North America. Philadelphia, PA: WB Saunders.

    Hyperemesis Education and Research Foundation website. Available at: http://www.helpher.org.

    Kasper DL, Braunwald E, Fauci AS, Hauser SL, Longo DL, Jameson JL, eds. Harrison’s Principles of Internal Medicine. 16th ed. New York, NY: McGraw-Hill Companies, Inc; 2005.

    Mahan LK, Escott-Stump S, eds. Krause’s Food, Nutrition, and Diet Therapy. 10th ed. Philadelphia, PA: WB Saunders Company; 2000.

    Marx J, et al. Rosen's Emergency Medicine. 7th ed. St. Louis, MO: Mosby, Inc., 2009.

    National Organization for Rare Diseases website. Available at: http://www.rarediseases.org

    Nausea and vomiting in pregnancy. EBSCO DynaMed website. Available at: https://dynamed.ebscohost.com. Updated October 2010. Accessed October 25, 2010.

    Quinlan JD, Hill DA. Nausea and vomiting of pregnancy. Am Fam Physician. 2003;68:121-128. American Family Physician website. Available at: http://www.aafp.org/afp/20030701/121.html. Accessed August 12, 2005.

    Sadock BJ, Sadock VA, eds. Kaplan and Sadock’s Synopsis of Psychiatry: Behavioral Sciences/Clinical Psychiatry. 9th ed. Philadelphia, PA: Lippincott, Williams and Wilkins; 2003.

    Wise MG, Rundell JR, eds. The American Psychiatric Publishing Textbook of Consultation-Liaison Psychiatry: Psychiatry in the Medically Ill. 2nd ed. Washington, DC: American Psychiatric Publishing, Inc.; 2002.

    Revision Information

  • Join WellZones today.

    Make a Change For LifeLearn more

    Wellmont LiveWell is creating a new tradition of wellness in the mountains by providing individuals with tools and encouragement to live healthier lifestyles.

  • HeartSHAPE Spotlight

    At risk for a heart attack? Learn more

    Fight heart disease early and prevent heart attacks with HeartSHAPE® - a painless, non-invasive test that takes pictures of your heart to scan for early-stage coronary disease.

  • Calories and Energy Needs

    Calorie NeedsLearn more

    How many calories do you need to eat each day to maintain your weight and fuel your physical activity? Enter a few of your stats into this calculator to find out.

  • Ideal Body Weight

    Ideal Body WeightLearn more

    Using body mass index as a reference, this calculator determines your ideal body weight range. All you need to do is enter your height.

  • Body Mass Index

    Body Mass IndexLearn more

    This tool considers your height and weight to assess your weight status.

  • Can we help answer your questions?

    Wellmont Nurse Connection is your resource for valuable health information any time, 24 hours a day, seven days a week. Speak to a Nurse any time, day or night, at (423) 723-6877 or toll-free at 1-877-230-NURSE.