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  6. Beyond Morning Sickness: Hyperemesis Gravidarum
  1. Knowledge and News on Women: OWH Blog

Beyond Morning Sickness: Hyperemesis Gravidarum

Knowledge and News on Women’s Health (KNOWH) blog from FDA Office of Women’s Health


Improving maternal health through education

Pregnant woman_nausea

The FDA Office of Women’s Health (OWH)—as part of a larger Department of Health and Human Services initiative—strives to improve maternal health. We are committed to supporting safe pregnancies and childbirth, eliminating pregnancy-related health disparities, and improving health outcomes for parents and infants. 
OWH conducts research and promotes initiatives that facilitate FDA regulatory decision-making and advance the understanding of sex differences and health conditions unique to women. As part of our mission, we team with various FDA and external partners to offer scientific and educational events

In 2023, as part of our OWH Scientific Series lectures for FDA and HHS staff, OWH invited Marlena Schoenberg Fejzo, PhD, Clinical Assistant Professor of Population and Public Health Sciences in the Center for Genetic Epidemiology at the Keck School of Medicine, University of Southern California, to present on hyperemesis gravidarum (HG), the most severe form of nausea and vomiting during pregnancy. To broaden awareness of this important topic and to offer continuing education credit to health professionals, OWH made this lecture recording publicly available

What should I know about hyperemesis gravidarum (HG)?

Below you will find some key information about HG. If you are experiencing symptoms, or have other concerns about your pregnancy, please speak with your health care provider. 

If you are pregnant and have severe nausea (for example, you are unable to drink for more than 8 hours or eat for more than 24 hours), seek medical care immediately. More from CDC: Urgent Maternal Warning Signs.

What is hyperemesis gravidarum? 

The vast majority of people experience nausea during pregnancy, often referred to as morning sickness, especially in the first three months of pregnancy. HG is the medical term for the most severe form of nausea and vomiting during pregnancy. It is more extreme than morning sickness. HG can lead to weight loss and dehydration, and may require intensive treatment. 

“Every living moment was torture.”


-- Dr. Marlena Fejzo on her experience living with HG

What causes hyperemesis gravidarum?

Recently published research findings indicate that a hormone produced by the fetus/placenta known as GDF15 appears to be the primary cause of morning sickness and hyperemesis gravidarum. The severity of nausea and vomiting may be determined by a woman’s sensitivity to the hormone-women exposed to lower levels of GDF15 before pregnancy experience more severe symptoms. For more information on possible causes, see this OWH lecture on HG research, which also offers CE credit for health professionals. 

How do I know if I have hyperemesis gravidarum?

People with HG often experience vomiting, which can lead to weight loss and dehydration. Symptoms often last longer than morning sickness. If you have nausea and vomiting so extreme that you lose more than 5% of your pre-pregnancy weight, you may have HG. For example, if you weighed 170 pounds before pregnancy, this would be a weight loss of 13.5 pounds or more. Weigh yourself regularly and contact your health care provider if you are losing any weight during pregnancy, as they may want to monitor you more closely. 

How is it different from morning sickness? 

People with morning sickness can generally proceed with normal daily activities, but people with HG cannot.  While morning sickness can cause decreased appetite, low level nausea, or vomiting (at any time of day), morning sickness is different from HG because people with morning sickness are typically able to eat and drink fluids some of the time. One symptom of HG is not being able to drink enough fluid or eat enough food.

What are the symptoms of hyperemesis gravidarum?

Symptoms in pregnant patients may include:

  • Severe, persistent nausea
  • Vomiting more than 3 times a day
  • Salivating a lot more than normal
  • Weight loss (more than 5% of pre-pregnancy weight)
  • Signs of dehydration (dark urine, dry skin, weakness, lightheadedness, or fainting)
  • Constipation
  • Not being able to keep food or liquids down
  • Feeling dizzy or lightheaded
  • Headaches

Am I at risk? 

HG can happen in any pregnancy, but is a little more likely if you are pregnant with twins or multiple babies, or if you have a hydatidiform mole. You are at higher risk if you have had the problem in previous pregnancies, are prone to motion sickness, or if a female relative has had HG. 

You may be at higher risk if you weigh more than 170 pounds (77 kilograms), or have a history of menstrual pain, sensitivity to oral contraceptives, nausea before your period, migraine headaches, allergies, high blood pressure, or kidney or liver disease, among other risk factors. 

Can it be prevented?

No, you can’t prevent hyperemesis gravidarum.

Is hyperemesis gravidarum common? 

No. This serious condition affects 0.3-10.8% of pregnant people. It can have adverse health effects on both the patient and the fetus.

What treatments are available?

There are currently no medications approved by the FDA to treat HG. If your nausea and vomiting cause you to become dehydrated, you will need to receive fluids through your vein (intravenous therapy, also called an IV). You also may be given anti-nausea medicine. If nausea and vomiting is so severe that you and your baby might be in danger, you may be admitted to the hospital for treatment. If you cannot eat enough to get the nutrients you and your baby need, you may get extra nutrients either through an IV or a tube placed into your stomach. Learn more from the National Library of Medicine’s MedLine Plus.

When should I contact a medical professional? 

Contact your health care provider if you are pregnant and have any of the following symptoms: 

  • Severe nausea and vomiting
  • Signs of dehydration (dark urine, dry skin, weakness, lightheadedness, or fainting)
  • Unable to tolerate any fluids for over 12 hours
  • Lightheadedness or dizziness, or feeling confused
  • Blood in the vomit
  • Abdominal pain
  • Weight loss of more than 5 pounds or 2.7 kilograms (Weigh yourself regularly to watch for excessive weight loss)
During pregnancy or as a new mother, you may feel overwhelmed at times. Mental health support and resources are available through the National Maternal Mental Health Hotline. It is free, confidential, and available 24/7. Call or text 1-833-TLC-MAMA (1-833-852-6262)

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