Understanding hyperemesis gravidarum

Understanding hyperemesis gravidarum

What is hyperemesis gravidarum?

Many women feel sick (nausea) and/or vomit during early pregnancy, (morning sickness). In fact it can affect around 80% of pregnant women.  It usually starts from the early part of pregnancy and generally settles after 14 weeks but around 10% of women experience symptoms beyond 20 weeks. Symptoms can occur at any time not just in the morning. Thankfully, nausea and vomiting rarely has a negative effect on your baby’s health but it can be challenging for women physically and emotionally.

Hyperemesis gravidarum (HG) is a severe form of nausea and vomiting in pregnancy and affects around 0.3% - 3% of pregnancies. This ongoing severe nausea and vomiting can cause women to find it hard to drink and eat enough food and this puts them at risk of dehydration (lack of fluid in their body), weight loss and vitamin deficiences as the body is unable to retain and use food and fluids.

What are the symptoms?

  • Ongoing nausea and severe vomiting that does not subside and prevents you from eating, drinking, sleeping, working or leaving the house as normal
  • Passing small amounts of dark and smelly urine and less often than usual or pain on passing urine
  • Blood in the vomit
  • Weight loss of 5% or more of pre-pregnancy weight
  • Severe exhaustion, dizziness, confusion or fainting
  • Headaches not responding to paracetamol, high temperature (fever), shortness of breath
  • Jaundice (yellow skin)
  • Stomach pain, bleeding, diarrhoea or cramping

What causes hyperemesis gravidarum?

The exact cause of hyperemesis gravidarum (and nausea and vomiting in pregnancy in general) is not clearly understood. It is thought to be related to rising levels of human beta hCG hormone (also known as the pregnancy hormone). 

Severe nausea and vomiting in pregnancy can occur more frequently in women with conditions associated with higher hCG hormone levels such as molar pregnancies (a type of pregnancy where a baby doesn’t develop properly) and twin/multiple pregnancies.


Mild cases of nausea and vomiting can be managed by changes in diet, rest and anti-nausea medication. It is best to see your GP, Obstetrician or Midwife for support and treatment advice.

If there is ongoing nausea and vomiting for more than a few days, it is important to see a Doctor early for an assessment, diagnosis, treatment and plan of care.  Most women will be given advice on their diet and often prescribed a variety of medications and supplements to help improve their symptoms.

Some women may need to be admitted to hospital for close monitoring, medication and intravenous fluids.

It is important that all women with hyperemesis gravidarum have regular follow-up with their usual antenatal care provider such as their GP, Obstetrician, Midwife and/or Antenatal Clinic, for ongoing check-ups of their and their babies health and wellbeing.

Complementary therapies

Some women who experience mild to moderate nausea and vomiting may find ginger helpful in relieving their symptoms. However, the effectiveness of ginger for women experiencing hyperemesis gravidarum has not yet been looked at.

Acupressure applied by finger pressure or wristband and electrical stimulation has been found to reduce symptoms of nausea and vomiting and hyperemesis gravidarum. But neither acupuncture nor hypnosis have been found to be effective treatments in either conditions.

Tips to relieve symptoms for nausea and vomiting

  • Eating small but frequent meals
  • Eat and drink slowly and chew foods well
  • Avoid having drinks with meals
  • Rest after mealtimes and make sure you are having lots of rest and sleep in early pregnancy
  • Try to eat something plain as soon as you wake in the morning such as a dry cracker or a slice of toast
  • Before going to bed, try and have a snack that contains protein and carbohydrate
  • Drinking fluids little and often rather than large amounts
  • Avoid high fat, fried or spicy foods
  • Try to introduce low-fat and protein-rich foods
  • Avoid triggers like a particular smell if they bother you and keep rooms well ventilated when cooking and if possible, ask someone to help prepare the food
  • Try and reduce any stress if possible

Will I get it again in future pregnancies?

As nausea and vomiting in pregnancy is so common, the risk of having these symptoms again in future pregnancies is high (up to 83%). But the risk for hyperemesis gravidarum reoccurring is much lower at around 15-26%. 

It is a good idea to see a GP or Obstetrician when planning a further pregnancy or in the early stages of your next pregnancy so that they can give information and advice and plan for early and effective management should any symptoms begin.

Further information and support

Mater Pregnancy Assessment and Observation Unit: 07 3163 7000



Mater Babies
This Year
This Month
= six + eight

Was this information helpful?

For urgent assessment at any stage of your pregnancy, please present to your nearest emergency centre or Mater Mothers’ 24/7 Pregnancy Assessment Centre in South Brisbane.

Was this helpful?
 Security code