Ayesha Curry reveals she shares Duchess of Cambridge's pregnancy struggle

At four months pregnant, Ayesha Curry thought that the nausea and restless nights would be over. But she's still struggling. That’s because Curry shares something in common with Catherine, Duchess of Cambridgehyperemesis gravidarum.

“Not feeling super royal,” the cookbook author and TV host wrote in her lifestyle community goInspo. “Every pregnancy is different for every woman! This is my third pregnancy and I’ve gotta tell ya, this one has topped the cake when it comes to being tough and exhausting. I️ simply cannot wait to have this baby and feel like ‘myself again.’”

Ayesha Curry is experiencing hyperemesis gravidarum with her third pregnancy. Getty Images

Hyperemesis gravidarum, which affects up to 3 percent of all pregnant women, causes severe vomiting, nausea, weight loss and electrolyte imbalances. It is not morning sickness.

“I want to distinguish the hyperemesis from the more common nausea and vomiting of pregnancy,” said Dr. Hyagriv Simhan, division director of maternal-fetal medicine and medical director of obstetrical services of Magee Womens Hospital of UMPC.

“It is subjectively more severe and also comes with physical manifestation like losing weight, dehydration and abnormal electrolytes.”

While most women experience significantly less nausea and vomiting after their first trimester, women with hyperemesis gravidarum continue experiencing nausea and vomiting — in some cases until they deliver.

“The good thing about pregnancy is that it is nine months. The bad thing about pregnancy is that it is nine months, nine long months for some,” said Dr. Christine Greves, a doctor at the Center for Obstetrics and Gynecology at Orlando Health.

Never miss a parenting story with the TODAY Parenting newsletter! Sign up here.

Experts remain unsure why some women experience it and others do not. Women pregnant with girls, those with a family history of it, those who have previously taken estrogen, such as in birth control pills, or those experience migraines are more likely to have it.

Curry, whose husband is Golden State Warriors player Steph Curry, admitted that constantly battling nausea and being unable to eat is making her feel blue.

Ayesha Curry shows Megyn Kelly how to make a roast chicken dinner in one pan

More Megyn Kelly videos

“This all has got me in a funk that I️ can’t seem to shake,” she wrote. “I️ am truly very very sad. When you can’t do what you love all of a sudden because of an uncontrollable situation, it sucks.”

While moms-to-be feel miserable, hyperemesis gravidarum does not often impact the babies’ health.

“Generally, hyperemesis affects women more than babies,” Simhan said. “(Still) her health can affect the baby.”

Doctors recommend that patients first try lifestyle changes, such as adding ginger or following the BRAT (bananas, rice, applesauce, toast) diet. Something called a sea band presses on a pressure point on the wrist and that can reduce nausea in some. When this doesn’t work, doctors can prescribe different pharmaceutical treatments, such as Diclegis, a combination of B6 and an antihistamine, or Zofran, a drug used to treat nausea in patients undergoing chemotherapy.

“We don’t recommend adding this whole list. Try one see if it works, (if not) try another,” Simhan said.