Underwood, 35, who is already mom to sonIsaiah Michael, 3, with Fisher, 38, announced the news on Wednesday, revealing little Jacob was born on Monday, Jan. 21.

“It has been a rough few years with the miscarriages and the accident and they didn’t even know if they’d get to this point.”

“They’re feeling truly blessed,” the source added.

Carrie Underwood/Instagram

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Mike Fisher and son Jacob.Carrie Underwood/Instagram

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Shortly after Underwood shared Jacob’s birth announcement, which included photos of the newborn from the hospital, Fisher shared acelebratory postof his own and touched on their tough journey.

Mike Fisher with sons Isaiah and Jacob.Carrie Underwood/Instagram

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“We didn’t know if Izzy would ever have another sibling but we learned through it all that God is in control and his timing is perfect.”

Jacob’s birth came nine months after Underwood received40 to 50 stitches in her faceand underwentsurgery on her broken wristafter aNovember 2017 fall on the stepsof her Nashville home.

In addition, she revealedshe suffered three miscarriagesfrom 2017 to 2018. During an emotional interview withCBS Sunday Morningin September, she opened up about her challenging fertility struggles.

Explaining her reaction to the heartbreak, the “blessed” star said, “My son,Isaiah, is the sweetest thing. And he’s the best thing in the world. And I’m like, ‘If we can never have any other kids, that’s okay, because he’s amazing.'”

source: people.com