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Hyperemesis Gravidarum: What Is Kate Middleton’s Pregnancy Sickness?

Hyperemesis Gravidarum: What Is Kate Middleton’s Pregnancy Sickness?

No, the Duchess of Cambridge is not suffering from “morning sickness”, but a debilitating illness called hyperemesis gravidarum. Here, we share an exclusive chat with the lead midwife of a world-renowned maternity hospital about hyperemesis gravidarum.

It was fatal in the past, and it is still the second biggest cause of hospitalisation in the first half of pregnancy.1 And yet hyperemesis gravidarum, the debilitating illness suffered by the Duchess of Cambridge is still all too often referred to as “morning sickness”. Some Twitter users have even accused the devoted mother of being a “drama queen” or snarked about their own ability to carry on after a “morning puke”.

But experts have hit back at these claims, with leading US Ob-Gyn Dr Jennifer Ashton tweeting: “From an OB standpoint, #hyperemesisgravidarum is severe morning sickness like Hurricane Harvey was a little bit of rain.”

We sat down with Stephanie Pease, Lead Midwife for Private Maternity Services at Queen Charlotte’s & Chelsea Hospital, to separate fact from fiction.

What Is Hyperemesis Gravidarum?

Hyperemesis gravidarum (HG) is a pregnancy complication involving intense nausea, vomiting, loss of weight and often dehydration and faintness. In many cases the effects of HG will improve by the 21st week of a woman’s pregnancy, but can actually last the whole way through. One in every 100 pregnant women may experience HG2 but many women are reluctant to talk about it.

Private Pregnancy UK can help you find the right Private Maternity Care Hospital or Clinic for you and your pregnancy journey.

How Serious Is Hyperemesis Gravidarum?

“HG is significantly more serious than morning sickness,” Ms Pease told us. “We’re talking about prolonged nausea and vomiting – up to 50 times a day. Women are often hospitalised and forced to undergo drip feeding to replace lost fluids because they are unable to tolerate any food or fluids over a sustained period.

“HG is unlikely to harm the baby if treated properly and the woman receives intensive midwifery and obstetric support in the early part of the pregnancy. But HG can be a debilitating condition, having a significant impact on the woman and her family. Prolonged HG can lead to significant weight loss and subsequent small babies. In fact, in very, very severe cases where the woman’s health has been at critical risk, HG sufferers have had to take the excruciating decision to terminate their pregnancies.”

In other words, this is no mere morning sickness.
The folks over at HER Foundation, the charity dedicated to improving research and education on HG, helpfully posted this comparison chart on their website for anyone still trivialising this serious condition.3

Morning SicknessHyperemesis Gravidarum (HG)
You lose little, if any weight.

Nausea and vomiting do not interfere with your ability to eat or drink enough each day.
You vomit infrequently and the nausea is episodic but not severe. You have significant discomfort.

Traditional remedies like diet or lifestyle changes are enough to help you feel better most of the time.

You typically improve after the first trimester, but may be queasy at times throughout pregnancy.

You may feel depressed, especially if you have severe nausea, but are able to be your usual self most of the time. You’ll likely forget the unpleasantness after delivery.

You lose 5-20lbs or more.

Nausea and vomiting cause you to eat very little and get dehydrated if not treated.

You may often vomit bile or blood. Nausea is usually moderate to severe and constant.

You’ll probably require fluid hydration through an IV and/or medications to ease symptoms.

You usually feel some relief by mid-pregnancy, but may be nauseous and vomit and/or until late pregnancy.

You will likely be unable to work for weeks or months, and may need help caring for yourself.

You may feel anxious about what lies ahead. You will likely become depressed due to misery and physical depletion. More severe HG is often traumatic and may impact you for years to come.

You usually feel some relief by mid-pregnancy, but may be nauseous and vomit and/or until late pregnancy.
You will likely be unable to work for weeks or months, and may need help caring for yourself.

What Causes Hyperemesis Gravidarum?

The precise causes of HG aren’t known and it can potentially happen to anyone. However doctors say women who are more at risk include4, 5:

  • Multiple pregnancy mothers-to-be
  • Women with previous experience of HG
  • First time mothers-to-be
  • Obese women
  • Women with a history of eating disorders
  • Women from families with a history of HG
  • Women also suffering trophoblastic disorder (pregnancy-related tumours)

How is Hyperemesis Gravidarum Treated?

Treatment will depend on the severity of HG a woman is experiencing, but can include:

  • More frequent antenatal care
  • Anti-sickness drugs
  • Hospitalisation
  • Intravenous fluids
  • Vitamins/iron therapy
  • Slow re-introduction to diet and fluids
  • More measures to protect against deep vein thrombosis, and treatment for DVT if necessary (HG carries an increased risk of DVT)
  • General help/support with day to day activity

“The bottom line is,” Ms Pease concluded, “persistent HG can have a huge impact on a woman’s physical and psychological wellbeing.”

Ergo, women with HG need sympathy, not snark. Get well soon, Duchess, we’re all thinking of you!

Queen Charlotte’s & Chelsea Hospital is a world-renowned maternity hospital offering exceptional level of care for women and their babies. To discuss delivering your baby here, call 020 3313 1466 or email



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