Hyperemesis gravidarum (Hyper-em-esis grav-i-dare-um) may sound like a fictional Harry Potter spell, but it’s actually a pregnancy condition that has received a lot of media attention recently. Duchess Kate Middleton endured hyperemesis gravidarum, or HG, throughout all three of her pregnancies, and comedian Amy Schumer shared her experience with it on social media throughout her pregnancy.

What is it? The condition is characterized by intense vomiting and nausea throughout pregnancy. Most women suffer from mild-to-moderate nausea and vomiting during the first trimester of pregnancy, which is called morning sickness, but HG is not the same. A pregnant woman with HG experiences severe, persistent nausea and vomiting, cannot eat or drink an adequate amount, loses weight and is dehydrated.

Doctors aren’t sure what causes the condition and many think hormone levels may play a role. It is more common in a woman’s first pregnancy, in women who are obese, in women whose pregnancies involved multiple babies or in women prone to motion sickness.

Women diagnosed with HG work with their doctors to determine the best treatment for their individual pregnancy. Most women are hospitalized for a short period of time to receive an IV that will replenish the body’s fluids and encourage the body to rest. Amy Schumer and Kate Middleton were both hospitalized during their pregnancies. Anti-vomiting medications may also be prescribed to lessen the severity.

Fortunately, babies aren’t usually affected by their mothers’ conditions and are born at a healthy weight and size. If you think you may be suffering from HG, speak with your doctor.