Kate Middleton makes a public appearance just days before being admitted to hospital
The pregnant Duchess of Cambridge is currently in King Edward VII Hospital being treated for Hyperemesis gravidarum.
The condition is an acute form of morning sickness, in which severe vomiting leads to dehydration, weight loss and the risk of nutrition deficiency. Hyperemesis gravidarum occurs during the first trimester, between six and 12 weeks, but can last 21 weeks or more. If not treated, the condition can result in complications for both mother and baby.
The cause of this condition, which is believed to affect one in 50 women, is not fully understood. However, it is suggested to be an adverse reaction to the hormone human chorionic gonadotrophin (hCG), which is produced during pregnancy.
Intense vomiting stops women from holding down food and liquid, and so treatment is through fluids given intravenously.
It is not possible to prevent Hyperemesis gravidarum. However, it is vital to recognise it and seek treatment promptly. Symptoms include weight loss, dizziness and feeling tired, alongside headaches, palpitations and confusion caused by dehydration.
In the early stages of Hyperemesis gravidarum, women are told to rest and eat regular, small amounts of dry food such as crackers or toast.
Other remedies include eating ginger, drinking ginger tea and wearing travel sickness bands. Women should also take supplementary nutrients such as folic acid, vitamin D and Omega-3.
Acupuncture is also a suggested form of therapy, which calms the increased energy levels seen during pregnancy and can help nausea to subside.