The Duchess of Cambridge is not alone in suffering such bad morning sickness that she needs hospital treatment.
Doctors at Leicester Royal Infirmary see more than 100 women a year with hyperemesis gravidarum – acute morning sickness.
The symptoms are usually so severe it is impossible for women to keep any fluids down.
This can lead to dehydration and weight loss.
Dr Angie Doshani, a consultant obstetrician and gynaecologist at the University Hospitals of Leicester NHS Trust, said: "Early pregnancy is pretty much a rollercoaster ride, but women suffering from HG (hyperemesis gravidarum) should not suffer in silence.
"There is help available. Sometimes they feel as if they are a failure if they come into hospital or that something is going to go wrong.
"They shouldn't feel this. Usually by 16 weeks the vast majority of cases will settle down, although some do last right through pregnancy.
"The earlier women get help the better so we can manage the condition. It is important they are hydrated and getting the right nutrients for themselves and the developing baby."
Dr Doshani said the condition was more common in first-time mums and in those expecting twins.
Sikhathele Ngwenya, from St Matthew's, Leicester, has a daughter and a son and is 14 weeks pregnant with her third baby.
She has suffered from hyperemesis gravidarum each time.
She is hoping media coverage about the condition will help make other sufferers realise they are not alone.
The 31-year-old said: "I thought I was the freak and the only one feeling this sick but now I know this is not the case.
"I have been in hospital twice with this pregnancy and expect to be in and out as I do become dehydrated. It is really horrible and very stressful when you keep vomiting and you can't keep anything down.
"It is also very painful. I was in so much pain with my last pregnancy that doctors thought it was appendicitis.
"It was just as bad when I had my other two children and it lasted for the first seven months of the pregnancy. I am hoping I will be able to be at home to enjoy Christmas."
Hilda Chisi, from Hamilton, Leicester, has had to have three days of hospital treatment because she became so dehydrated after being sick about 10 times a day and not being able to keep anything down.
Her weight plummeted from 9st 13lb to 8st 3lb.
The 37-year-old, who is 12 weeks pregnant with her fourth baby, said: "It began when I was about four weeks pregnant. At first I just felt very tired and had no energy at all.
"Then I started being sick and became weaker and weaker."
It is the second time she has been admitted to hospital because of the condition.
Mrs Chisi said: "Having the fluids do make me feel better.
"I had this sickness with all my other pregnancies and am hoping it will stop when I get to about 20 weeks, which is what happened before.
"It is not a nice experience."
