As the newly-pregnant Duchess of Cambridge is hospitalised with an extreme form of morning sickness, doctors discuss the nightmare condition.
By Lisa Salmon
As the nation celebrates the happy news that the Duchess of Cambridge is expecting her first child, there's a tinge of pity for the royal mother-to-be as well, as she lies in hospital suffering with severe sickness.
The 30-year-old has hyperemesis gravidarum (HG), an extreme form of pregnancy-induced sickness suffered by up to 2% of expectant mothers.
Normal morning sickness (known medically as nausea and vomiting in pregnancy, or NVP) affects around 70% of pregnant woman, and causes some degree of vomiting and discomfort commonly during the first trimester (12 weeks) of pregnancy. HG, on the other hand, is a different kettle of fish altogether...
Those unfortunate enough to develop it are constantly sick morning, noon and night and unable to keep any food or drink down. Other symptoms include dehydration, low blood pressure, tiredness, dizziness and weight loss, and HG can go on for much longer too - sometimes, although rarely, for the entire pregnancy.
The condition is so severe that some expectant mums have even terminated their pregnancies, rather than continue with the torture of constant sickness.
It's not yet known how many weeks pregnant the Duchess is, although St James's Palace said the royal couple only became aware of the pregnancy "recently", and it's assumed that Kate hasn't passed the 12-week point yet.
In fact, it's understood that she and her husband Prince William only publicly revealed their news due to her being hospitalised.
Dr Roger Gadsby, chairman of the charity Pregnancy Sickness Support, says: "We don't know, as it's her first pregnancy, how long the sickness will last - it might go off at the usual time of 12-14 weeks, but it'll certainly get worse until she's 10 weeks.
"But just because it's very severe now doesn't mean it's going to go on right through the pregnancy. It only goes on for that long in a very small minority of women, and I trust it won't happen to the Duchess."
Women with NVP usually receive a diagnosis of HG if they're ill enough to be admitted to hospital, where treatment involves being put on an intravenous drip to replace lost fluids, and anti-sickness drugs.
It's unclear what causes it, though HG is more common in first and multiple pregnancies, and hormones are thought to be involved.
"I wish we knew what causes it," says former GP Dr Tony Barnie-Adshead, a Pregnancy Sickness Support trustee. "There's no doubt that it's associated with the hormones secreted by the placenta. It's certainly a very complicated process."
Thankfully, the unborn baby is rarely affected by HG.
"The baby is the perfect parasite - it looks after itself and seems to get the best of what's going," says Dr Barnie-Adshead.
However, if the mother has severe HG and loses weight as a result, the baby may be a low birth weight.
"But other than that, the baby's fine - you don't get foetal abnormalities associated with hyperemesis," says Dr Barnie-Adshead. "It's not a bad sign for the outcome of the pregnancy, but it's awful for the ladies who go through it."
Consultant obstetrician Dr Daghni Rajasingam, spokesperson for the Royal College of Obstetricians and Gynaecologists, says women who suffer as severely as Kate are usually admitted to hospital for observation and to treat dehydration with intravenous fluids. "However, this usually only means a few days in hospital," she says.
Indeed, in a statement released after the Duchess's admission to the King Edward VII Hospital in central London, St James's Palace said: "As the pregnancy is in its very early stages, Her Royal Highness is expected to stay in hospital for several days and will require a period of rest thereafter."
Dr Rajasingam adds: "The best advice for anyone suffering from hyperemesis gravidarum is to get plenty of rest and drink lots of fluid.
"The condition usually subsides by week 12 and with early diagnosis and treatment, there's no reason why we shouldn't expect a healthy pregnancy."
Rosie Dodds, senior policy adviser for the parenting charity NCT, says that while the charity is "thrilled" about the Duchess's pregnancy, it's very sorry to hear about her hospitalisation.
Dodds says a variety of strategies can help women ease the symptoms of nausea and vomiting when pregnant, including avoiding possible trigger smells like smoke, and avoiding fatty foods. "Although there's limited evidence, the use of ginger, vitamin B6 and acupressure have also been found to be effective for some women," she says, athough she advises all pregnant women should check with their doctor or midwife beforehand.
She says the traditional sickness remedy of eating dry foods, like toast, is unlikely to do any harm and points out: "Some women find they can only manage a few foods, and not necessarily nutritious ones at that. In this case it's still better to eat whatever stays down than to go hungry, as that's likely to make the sick feeling worse.
"We wish William and Catherine the best of luck with the pregnancy and hope that the Duchess is feeling better soon."
No doubt sentiments shared by millions - especially other women who've suffered with HG. As Dr Barnie-Adshead stresses: "This condition is an absolute nightmare for the women who suffer from it."
:: For more advice and information about pregnancy sickness, contact Pregnancy Sickness Support on 0247 638 2020, or visit www.pregnancysicknesssupport.org.uk