Services & Conditions
Hyperemesis Gravidarum

Hyperemesis Gravidarum


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, morning sickness). Morning sickness affects anywhere between 70% to 80% of pregnant women. HG is estimated to occur in up to 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 (hCG)—hyperemesis is most severe during the period of highest hCG levels
  • Hyperthyroidism —may be a result of high hCG levels
  • High levels of estrogen
  • A multiple pregnancy
  • Brain nausea-control-center sensitivity to pregnancy changes
The Brain May Be Cause of Nausea
Brainstem and brain
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Risk Factors

Factors that may increase your chance of HG include:

  • History of HG in previous pregnancies
  • Molar pregnancy—an abnormal mass made up of placental tissue which 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


HG may cause:

  • Severe and persistent vomiting, beginning 4 to 6 weeks after conception, peaking at 9-13 weeks, and usually improving and ending by 14-20 weeks
  • Weight loss of greater than 5% of original, pre-pregnancy body weight
  • Decrease in urine output
  • Dehydration
  • Rapid heartbeat
  • Headaches
  • Confusion
  • Lightheadedness and fainting


Your doctor will ask about your symptoms and medical history. A physical exam will be done. Tests may include the following:

  • Blood tests
  • Urine tests
  • Weight measurement—to determine if you have lost weight
  • 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:


Many of the conditions that lead to HG are not preventable. To help reduce your chance of nausea during pregnancy:

  • Avoid smells, foods, or other things that stimulate nausea
  • Eat frequent, small meals
  • Do not allow yourself to get too hungry or too full

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