Most people experience some nausea and vomiting during the first three months of pregnancy. Hyperemesis gravidarum is much rarer and more impairing than regular morning sickness (even a pretty bad case), involving severe and continuous vomiting and nausea. 

Although natural home remedies can often help mild cases of hyperemesis gravidarum, more severe cases may require hospitalization to protect you and your baby. 

What is hyperemesis gravidarum?

Hyperemesis gravidarum is debilitating and persistent nausea and vomiting during pregnancy. Your doctor may diagnose you with the condition if you've lost more than 5% of your pre-pregnancy weight.[1]

Severe cases of hyperemesis gravidarum can lead to problems like dehydration and poor weight gain, which sometimes require hospitalization. Fortunately, as miserable as it makes you feel, hyperemesis gravidarum usually does not harm your baby.

What causes hyperemesis gravidarum?

Like many pregnancy symptoms, hyperemesis gravidarum is thought to be caused by pregnancy hormones — specifically rising levels of human chorionic gonadotropin (hCG).[2] 

However, a 2023 study has found that a single hormone, known as GDF15, could be the primary cause of morning sickness during pregnancy.[3]

Researchers concluded that the amount of GDF15 in a woman's bloodstream is linked to how severe her morning sickness is. Women with intense morning sickness had abnormally high levels of GDF15 in their systems, but those who were exposed to GDF15 before pregnancy didn't have a strong reaction to it when they were expecting. GDF15 is released by the growing fetus and also by various tissues in the body in response to stress, including infections.

What are the symptoms of hyperemesis gravidarum?

Symptoms of hyperemesis gravidarum include:

Morning sickness vs. hyperemesis gravidarum: What's the difference?

Think of morning sickness as a continuum, with hyperemesis gravidarum at the extreme and severe end of the spectrum. Compared to more manageable nausea and vomiting during pregnancy, hyperemesis gravidarum symptoms are persistent and significantly more acute. 

If you're unsure whether you're suffering from hyperemesis gravidarum, talk to your practitioner. Your doctor will discuss your symptoms and may run a few tests, including checking your complete blood count and electrolyte levels, as well as looking for ketones in your urine. 

They'll also rule out other potential causes for severe vomiting and nausea, including food poisoning, a thyroid or gallbladder condition, or an ulcer. (These conditions tend to cause other symptoms like headache, fever or a swollen thyroid gland.)

When does hyperemesis gravidarum start?

Symptoms of hyperemesis gravidarum start in the first trimester, usually between week 4 and week 8 of pregnancy, with most diagnoses happening around week 9. It usually starts to lift on its own between week 12 to week 16, with most cases resolved by week 20 — although it can sometimes continue throughout pregnancy.

How common is hyperemesis gravidarum?

Hyperemesis gravidarum occurs in fewer than 3% of all pregnancies. You may be at greater risk of the condition if you are:

  • A first-time mom
  • Younger
  • Obese
  • Carrying multiples
  • Prone to getting car sick or migraines
  • Undergoing extreme (more than everyday) stress 
  • Diagnosed with hyperthyroidism (high thyroid levels)
  • Deficient in vitamin B or other nutrients
  • Pregnant with a girl 

You're also more likely to have hyperemesis gravidarum if your mom or sister had it, as well as if you suffered from it in a previous pregnancy. 

Coping with mild hyperemesis gravidarum

If your symptoms are relatively mild and you're able to keep some food and liquid down, try natural methods used to fight morning sickness, including:

  • Noting and trying to avoid your hyperemesis gravidarum triggers, which may include: certain foods or smells, riding in the car, bright lights, certain noises or sounds and tight-fitting clothes
  • Eating foods with real ginger, such as ginger tea, ginger candies, ginger ale or ginger cookies
  • Eliminating fatty and spicy foods, which are more likely to cause nausea
  • Grazing on small, high-carb and high-protein meals throughout the day, which are easier to digest and keep acids from irritating your stomach lining 
  • Drinking plenty of fluids — and keeping an eye on your urinary output (dark, scant urine is a sign you're not getting, or keeping down, enough liquids)
  • Wearing nerve-stimulation wristbands (such as Reliefband)
  • Trying hypnosis, which some moms-to-be report as helpful
  • Taking Epsom salt baths
  • Seeing a therapist, particularly if the nausea or pregnancy in general is causing you anxiety

If these strategies don't help, talk to your practitioner. For tough morning sickness cases, your doctor may recommend vitamin B6 (shown to relieve nausea and stress), doxylamine (found in over-the-counter sleep aids), or a combination of the two. Both medications have been shown to be safe if taken during pregnancy.

Keep in mind that even if you've heard about other people using marijuana as a remedy for nausea and vomiting, health experts stress that using pot during pregnancy is not safe and should be avoided completely.

Coping with severe hyperemesis gravidarum

Check in with your doctor if you:

  • Can't tolerate any foods for more than 12 hours
  • Feel lightheaded or dizzy
  • Have signs of dehydration
  • Have lost more than 5% of your pre-pregnancy weight
  • Have blood in your vomit
  • Have abdominal pain

Severe cases of hyperemesis gravidarum can lead to weight loss, dehydration, electrolyte imbalances, malnutrition and bleeding in the esophagus.

In some cases, your doctor may prescribe an anti-nausea drug. If you're severely dehydrated, you may require hospitalization, mostly for intravenous (IV) fluids and stronger anti-nausea medication, although you may receive tests to check your liver and pancreas function and possibly get a feeding tube. 

Once you're able to keep food down again, it's best to follow all of the same best practices that relieve less severe cases of morning sickness.

What should you do if you have hyperemesis gravidarum during pregnancy?

Talk to your doctor if your hyperemesis gravidarum symptoms are debilitating or even just concerning. Try to take it easy and care for yourself as best as you can. 

Also be sure to talk to your doctor if you're experiencing signs of anxiety or depression, which tend to be more common in pregnant women with hyperemesis gravidarum. You're not alone: For support from other moms who've been through it before, check out the HER Foundation.