This health risk led Kim and Kanye to use a surrogate for their third child

Kim Kardashian West and Kanye West just released some exciting news: North and Saint are getting a new sibling! The main difference so far with the reality star’s third pregnancy is that a surrogate is carrying the baby.

Kardashian West suffers from placenta accreta, and after two high-risk pregnancies, she’s not taking any chances this time around, reports People. But what exactly is this condition?

With placenta accreta, the placenta attaches itself too deeply to the uterine wall.

When a woman is pregnant, the placenta normally hooks right onto the uterine wall. But when placenta accreta occurs, the placenta attaches itself too deeply, according to the American Pregnancy Association (APA). This occurs in 3 out of every 1,000 deliveries a year, and there are three different levels of severity.

Kardashian West’s placenta accreta is the the most common (it accounts for 75 percent of all cases), while placenta increta and placenta percreta—when the placenta attaches deeper into the uterine muscle or all the way through it—are more rare and dangerous. But just because her condition isn’t among the highest of risk doesn’t change that it is indeed quite serious.

No matter which form a woman has, she can can experience life-threatening hemorrhaging, as well as damage to the uterus or other organs, says APA. To diminish the risk of the mother losing too much blood during birth, planned premature deliveries are often suggested (so as to control the delivery better), which can expose the baby to additional complications. In severe cases, the uterus is surgically removed after birth “to prevent serious blood loss that can occur if part, or all, of the placenta is left attached to the uterus after your baby is delivered,” according to Healthline.

“My doctor had to stick his entire arm in me and detach the placenta with his hand, scraping it away from my uterus with his fingernails.”

“My doctor had to stick his entire arm in me and detach the placenta with his hand, scraping it away from my uterus with his fingernails,” Kardashian West wrote on her website in 2013 about her first delivery. “My mom was crying; she had never seen anything like this before. My delivery was fairly easy, but then going through that—it was the most painful experience of my life.”

After enduring that pain during her first two pregnancies, Kardashian West wasn’t taking her chances on a third: There’s a high risk for reoccurrence in future pregnancies. So she found a surrogate who would help expand her family in the safest way possible.

“The entire family is over the moon. Kim had been looking for a surrogate for months until recently when she found the perfect candidate,” a source told People. “Given her health scares in the past, Kim felt the need to hire a surrogacy agency that helped serve as the liaison in finding a healthy woman who would be a great surrogate option for her and Kanye. Both of them have been super involved in the process.”

There’s no word on when baby number three is due, but one thing’s for sure: He or she is sure to make a grand entrance. The Kardashian West clan wouldn’t have it any other way.

Here are 10 unexpected changes that happen to your body during pregnancy. Speaking of surprising changes, you’ll never guess which healthy foods Serena Williams craved during her pregancy.