It’s official: Kate Middleton and Prince William are expecting their third child.
But as with her first two pregnancies, it’s also been announced that the Duchess of Cambridge is suffering from Hyperemesis Gravidarum, a rare condition that can be deadly in extreme cases.
So what exactly is it?
Hyperemesis Gravidarum (HG) strikes 1 to 3 percent of pregnant women and is a complication that causes excessive nausea and vomiting.
The sickness is so severe that it can leave suffers dehydrated, deficient in vital nutrients and unable to maintain a healthy weight as they struggle to eat or drink.
It’s also the second leading cause of hospitalisation during pregnancy (behind preterm labour), with other symptoms including fatigue, low blood pressure, rapid heart rate, fainting and headaches.
Unlike regular morning sickness, the condition may not clear up completely until the baby is born, although some women may start to feel better around the 20-week mark.
While a potential culprit may be the rapid hormonal changes that take place during the first trimester of pregnancy, the exact cause of HG remains unclear.
According to Baby Centre, there are possible risk factors, such as being overweight, carrying twins or triplets, or having had the condition in an earlier pregnancy.
Evidence also suggests that HG may run in the family, with a study from Norway published in the BMJ in 2010 finding that women whose mothers suffered from the sickness were three times more likely to have the same problem during their own pregnancy.
Generally, HG is not dangerous to the developing foetus if it’s treated. However, if the mum-to-be doesn’t receive adequate nutrients over a long period of time, it can impact the baby’s birth weight.
If you are suffering from these symptoms, it’s important to visit your doctor or specialist.