WITHIN HOURS of the breaking news that the Duchess of Cambridge is pregnant, my inbox started to fill up with missives from PR companies plugging products that claim to ease morning sickness.

I know from personal experience that none of them work.

And what Kate was hospitalised with is a much more serious complaint. She has hyperemesis gravidarum, which is a posh way of saying she is throwing up all the time, not just in the morning, because she is pregnant.

It is the same condition that historians believe killed Charlotte Bronte. The difference between Kate and Charlotte is that the former has access to the very best care modern medicine can offer while the latter lived at a time when entire families were wiped out by TB and women frequently died in childbirth.

Kate has my sincerest sympathies – as does any woman who finds herself in this predicament.

My own run-in with extreme pregnancy malaise began the day after I performed a pregnancy test and announced that I’d seen a faint pink line.

Within a week I was feeling so nauseated that I could barely eat. By the end of the first trimester I’d lost weight and become ketotic (when your body starts to burn protein instead of carbohydrates as fuel).

Secondborn, the cause of the sickness, has grown up with the tale of my interminable pregnancy. I didn’t have morning sickness as such, it was more of an ‘all-day and all-night stomach-turning grogginess and dyspepsia’. And it seemed to go on, and on, for pretty much ever. At night I had a bottle of Gaviscon by the bed and rarely slept for more than a couple of hours at a time.

I eventually discovered that eating cornflakes with milk gave me temporary relief and I’d get up several times in the night to help myself to a bowlful.

The Girl must herself be sick of hearing me say that the nausea lasted for the whole of the nine months. “And I never had a day of sickness with your brother,” I usually point out before adding, “but of course it was worth it.” Which it absolutely was. Although the experience definitely deterred me from any thoughts of further extending our family.

Sometimes hyperemesis gravidarum is so debilitating that sufferers beg for an abortion. Although this seems a drastic solution to the problem I can almost understand it. There is nothing quite as depressing as facing day after day feeling as if you have the worst travel sickness you’ve ever experienced and there’s nothing you can do about it. I imagine it is akin to having chemotherapy. And I don’t say that flippantly.

I found the whole experience particularly distressing as I had to care for a lively and demanding toddler while at times lacking the ability to even get out of bed in the morning.

This condition, which affects 1% of pregnancies, often passes by the 20 week stage – ‘normal’ morning sickness, which is much more common, usually eases off after the first trimester.

But the unlucky few will find their entire pregnancy blighted. I once met a former mayoress of Kirklees who admitted that she’d actually thrown up in the delivery room.

There are many theories about morning sickness but no real answers as to why women suffer from it.

One theory is that the nausea prevents pregnant women from ingesting substances that might be harmful to the foetus. In the past this would have included certain plants high in toxins and easily contaminated foods such as meat and fish. It is known that women who feel sickly in pregnancy and have a restricted food intake miscarry less than those who are not sick and therefore able to eat and drink whatever they want.

It is also thought that the nausea might be a reaction to the changing hormone levels.

My GP kept reassuring me that a queasy pregnancy was a strong pregnancy. It was my only comfort. I was advised to eat stem ginger, drink ginger tea, wear acupressure wrist bands and stay calm, although none of this did any good. There is, however, some research that shows women who are agitated or worried about their pregnancy tend to suffer more.

All I can say to anyone currently enduring pregnancy sickness is that it does pass – even if you have to wait nine months (I was miraculously cured the day I delivered Secondborn) – and you’re in good company.