Now that Kate Middleton is in her second trimester of pregnancy, the Duchess of Cambridge is reportedly “feeling great” after suffering from hyperemesis gravidarum earlier this year. “[She is] enjoying her later months of pregnancy… It’s amazing what a difference the later trimesters feel like compared to the early days, which she really struggled with more than ever this time,” a source close to the royal told Us Weekly in late December.

Kensington Palace first announced in September that Kate, 35, is expecting her third baby with husband Prince William, also 35. At the time, a royal spokesperson also confirmed Kate was again suffering from the same severe morning sickness she experienced while carrying older kids Prince George, 4, and Princess Charlotte, 2. Keep reading to find out more about Kate’s battle with hyperemesis gravidarum.

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(Photo Credit: Getty Images)

What is hyperemesis gravidarum?

While morning sickness is common and affects 70 to 80 percent of pregnant women, it usually occurs early on in the pregnancy and subsides after a few weeks. Hyperemesis gravidarum, on the other hand, is a more severe form of morning sickness that causes dehydration, vitamin and mineral deficits, and weight loss through frequent nausea and vomiting, according to WebMD.

The symptoms can be debilitating.

With morning sickness, women usually experience nausea that isn’t always accompanied by vomiting. But with hyperemesis gravidarum, nausea is almost always accompanied by vomiting, according to the American Pregnancy Association. Also with hyperemesis gravidarum, the symptoms of nausea and vomiting do not allow affected women to keep food down and it causes severe dehydration.

Kate was hospitalized because of it in the past.

During her two previous pregnancies with children George and Charlotte, Kate had to seek medical treatment because of hyperemesis gravidarum. Back in 2012, she was treated at London’s King Edward VII hospital for several days while she was in the early stage of pregnancy with George. She also suffered from the illness during her pregnancy with Charlotte, but she was treated for her symptoms at home at Kensington Palace. As Closer Weekly previously reported, Kate was rushed to a London hospital in late August — the start of her third pregnancy — and treated for an unknown illness. We now know the hospitalization was because of hyperemesis gravidarum symptoms.

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