"For Christians, for Jews, and for me, this time is a reminder of the death of firstborn sons. Sacrifice. Suffering. Mourning. Grief," the 32-year-old actress wrote on Instagram, as she reflected on her family's tragic loss last year.
"Last Easter was the worst night of my life. We held our firstborn son in our arms as he took his final breaths. We spent time in the hell that is watching your child die," she added. "This Easter is decidedly better. Despite that wretched Easter night, I can't ignore that this day also represents rebirth. Renewed hope."
Continuing, she wrote, "It is said that the word 'Easter' is derived from the goddess Eostre. Eostre, the goddess of fertility, symbolizes the birth of new life and the dawn of spring. And so it is for us."
Alongside the emotional message was a trio of photos featuring an easter basket for the couple's baby on the way, which included a rainbow onesie and a sign that read "I will not cause pain without allowing something new to be born."
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Another sweet photo also showed the couple's 5-year-old Decker Kate smiling outside in front of easter baskets for herself and all her siblings. Behind her also stood a sweet sign reading, "McCoy's a big bro!" adding that the family's new arrival will be "sprouting this spring."
As her post came to a close, Keough Bosworth included a touching message to her late son, as well as her father, Matt Keough, who died weeks after his grandson.
"We miss you, Mack-a-doodle. Thank you for sending us this sacred gift. You're a big brother! Tell Grandpa that I said he was right. He'll know what I mean," she wrote.
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In the months since her son's death, Keough Bosworth has continued to grieve the loss of her son, who died after having experienced "shoulder dystocia and a compressed umbilical cord" during his birth.
"Oh, 11. It's been 11 months since you were born. But that's not the only reason 11 hits me harder than the other months. 11 just has a way of doing that," she wrote earlier this month alongside a black-and-white photo with her son.
She went on to recall that the "first time an 11 blindsided me" was after her son was born weighing 11 lbs. and 4 oz. "Through the phone, I could hear the doctors and nurses frantically trying to revive you in the background. "11.... 11 pounds and 4 ounces," she wrote.
"I told him he heard wrong and he needed to ask again. And that was the first time an 11 blindsided me. Now, it happens when I see a friend's baby turn 2, or 3, or even 4 months old... and I see their sweet milestone signs," she continued, adding that it "takes a moment for the bitterness to fade and for the sweetness to take its place."
"So now, when people mention their big babies, I don't snarl anymore. I smile in my heart knowing I've birthed a member of the Big Baby Pack. Every time I happen to flip to page 11, or I pass a mailbox, or I hear the call of an order number, or I see 'sticks' on a baseball jersey, or I catch the clock at 11:11... instead of flashing back to excruciating moments on the night you were born, I feel your love knowing it's you popping in to say hi," she added as the post came to a close. "I guess what I'm saying, baby, is that the 11's are everywhere now. And so are you."