Severe morning sickness for the duchess

The duchess of Cambridge has been admitted to King Edward VII Hospital suffering from severe morning sickness.

Hyperemesis gravidarum is a rare condition which causes severe vomiting during pregnancy. The severity of the vomiting can cause dehydration, weight loss, and a build-up of toxins in the blood or urine called ketosis.

It affects 3.5 per 1,000 pregnant women.

Hyperemesis gravidarum is treated by giving women fluids intravenously and by anti-sickness tablets.

Daghni Rajasingam, a consultant obstetrician and spokeswoman for the Royal College of Obstetricians and Gynaecologists said: “The diagnosis is given when women cannot keep food or fluid down because she has severe vomiting. The women who are vomiting pretty much constantly, that cannot keep any nutrients down, they need to be admitted to hospital.”

She said the length of stay in hospital depends on each patient but many women are discharged in a matter of days.

The condition is thought to be caused by elevated levels of the “pregnancy hormone” hCG and is most common in the first 12 weeks of pregnancy, Ms Rajasingam added.

St James’s Palace has not announced how far along Kate is in her pregnancy, just confirming it is still in its “very early stages”.