Facebook's Mark Zuckerberg and wife Priscilla Chan expecting a baby

Facebookfounder andCEO Mark Zuckerberg his wife Priscilla Chan are expecting a baby girl.

Zuckerberg, 31, shared the "exciting news" in a post on Facebook today in which he also talked about the couple's struggle to start a family.

• Link to Mark Zuckerberg'sFacebook post (requires Facebook account)

He said the couple has been trying to have a child for a couple of years and have had three miscarriages along the way.

"You feel so hopeful when you learn you're going to have a child. You start imagining who they'll become and dreaming of hopes for their future. You start making plans, and then they're gone. It's a lonely experience," Zuckerberg wrote.

He said most people don't discuss miscarriages, but that after talking to his friends, he realized that it was very common, and that most couples went on to have healthy children.

"We hope that sharing our experience will give more people the same hope we felt and will help more people feel comfortable sharing their stories as well."

He added that the pregnancy is now far enough along that the risk of another miscarriage is very low "and we are very hopeful."

"We're looking forward to welcoming her into the world and sharing more soon when she's ready to come out and meet everyone!"

Zuckerberg and 30-year-old Chan, a doctor, were married in 2012.