The rare pregnancy condition which the Duchess of Cambridge suffers from can be deadly, medical literature shows.
Hyperemesis Gravidarum (HG), which strikes just 1 per cent of pregnancies, is a complication that causes excessive nausea and vomiting.
Unlike regular morning sickness, it doesn’t fade away with time. It is also considered to be the second leading cause of hospitalisation during pregnancy.
More than 1,000 abortions each year are linked to the severe pregnancy sickness – which can leave some women bedbound.
Hyperemesis Gravidarum is the medical terminology for excessive nausea and vomiting. The Duchess of Cambridge is a famous sufferer
The Duchess, 33, cancelled engagements last autumn as she battled HG
It may not clear up completely until the baby is born, although some symptoms may improve at around 20 weeks.
Some pregnant women are sick many times a day and are unable to keep food or drink down, which can have a negative effect on their daily life.
Many mothers-to-be may lose up to 10 per cent of their body weight when they are supposed to be gaining about 1lb a week.
This can trigger a build-up of toxins in the blood or urine known as ketosis as the body tries to compensate for lack of food.
Exactly how many pregnant women get HG is not known as some cases may go unreported, but it’s thought to be around 1 in every 100.
Signs and symptoms of HG include prolonged and severe nausea and vomiting, dehydration, low blood pressure and rapid weight loss.
In 2012, while expecting Prince George, she was admitted to hospital when HG left her severely dehydrated (pictured with Princess Charlotte in May 2015)
The Duchess of Cambridge is pregnant with her third child, Kensington Palace has announced (pictured on her wedding day on April 29, 2011)
Hospital treatment for these women is essential, as without intravenous feeding and fluids they are at risk of becoming dangerously dehydrated.
Until intravenous hydration was introduced in the 1950s, it was the leading cause of maternal death, Marlena Schoenberg Fejzo, a medicine researcher at the University of California, Los Angeles, previously told The Conversation.
But she warned that the condition is neither well-understood nor well-known, even with the ‘flurry of headlines’ after it was announced Kate was struck down by it.
The condition can also affect the baby’s development and there is a risk it will be premature or have a very low birth weight.
In severe cases, the sickness can trigger a miscarriage. It can also cause an abnormally fast heart rate in the mother, medical literature states.
The condition is thought to be caused by elevated levels of ‘pregnancy hormone’ HCG, or human chorionic gonadotropin, which increases after conception.
There is no cure but one of the most effective treatments is the drug Ondansetron, which is taken twice a day at a cost of £3.50 per pill.
Caitlin Dean, chairman of Pregnancy Sickness Support, previously said: ‘The severity of the condition should not be underestimated and the risks and complications of not treating it need to be appreciated.’
The Duchess, 33, cancelled engagements last autumn as she battled HG. And in 2012, while expecting Prince George, she was admitted to hospital when HG left her severely dehydrated.