Kate Middleton's Illness Not Dangerous, Sometimes Associated With Twins

Catherine, the Duchess of Cambridge poses for an official photograph flanked by members of the Irish guards as she visits Aldershot Barracks on St Patrick's Day in Aldershot on March 17, 2012. (Chris Jackson/AFP/Getty Images)Hyperemesis gravidarum, the reason newly pregnant Kate Middleton is in the hospital, is a rare but acute morning sickness that results in weight loss and accounts for about 2 percent of all morning sickness, doctors say.

The condition is sometimes associated with women having twins, experts said.
Women diagnosed with hyperemesis gravidarum have lost 5 percent of their pre-pregnancy weight, or 10 pounds, said Dr. Ashley Roman, a professor and OB/GYN at New York University Langone Medical Center.
It poses little danger to the tiny heir, doctors said.
"It's traditionally thought that nausea and vomiting is a sign of a healthy pregnancy," Roman said
Dr. Nancy Cossler, an OB/GYN at University Hospitals in Ohio said the condition does not cause loss of pregnancy or birth defects, but it can be a torture to endure.
"The biggest problem with this is how it interferes with your life," Cossler said. "Constantly feeling sick and puking is difficult."