NBC News' White House Correspondent Carol Lee announced she's currently six months pregnant, revealing that the baby has a rare congenital heart defect that requires surgery.

On Thursday, Lee announced that she is expecting her first child with husband Lt. Col. Ryan Harmon, telling Today Parents that the happy news comes after a miscarriage, and that their baby was conceived via IVF on their first transfer. The journalist, who is due in June, is also mom to son Hudson, 8.

With the announcement, the mom also revealed that her baby boy on the way was diagnosed with transposition of the great arteries, or TGA, when she was 16 weeks along. The newborn will have to undergo open-heart surgery within the first few days after being born, she said.

"I thought we were in the clear. I thought we were done crying," Lee, 43, tells Today. "The part that terrifies me the most is bringing him home. I'm basically going to stare at him 24 hours a day watching him breathe. I don't know how I am going to sleep."

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Lee shares that her husband, 36, remains "really positive" while he "keeps reminding me that we have the best doctors and everything is going to be okay."

"Our job is to set our baby up to thrive. This has been a difficult journey with a lot of setbacks, but we still feel incredibly lucky," she says.

According to the Mayo Clinic, TGA is a "serious but rare heart defect" where the "two main arteries leaving the heart are reversed."

The experts add: "Corrective surgery soon after birth is the usual treatment for transposition of the great arteries. Having a baby with transposition of the great arteries can be alarming, but with proper treatment, the outlook is promising."

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