"The Bachelor" alum Sarah Herron and fiance Dylan Brown are grieving the death of her newborn son who was born prematurely at 24 weeks last week.

The reality star revealed the devastating news on Instagram Wednesday by posting a carousel of pictures and a video, including one image featuring herself and her fiance embracing their baby boy, whom they named Oliver Brown, in the hospital bed. Brown can be seen planting a kiss on Herron's forehead in the touching photo as the couple mourned their loss in the caption.

"On January 28th, at 24 weeks old, our beautiful son Oliver Brown was born," Herron, 36, wrote. "He passed away in his dad's arms shortly after. There are no words for the magnitude of loss and pain we're experiencing. It's beautiful and simultaneously tragic. He had my nose and his dad's mouth and long fingers."

"Oliver, our IVF miracle defied so many odds and fought through so many hard milestones to be here, but the higher powers still had other plans for the three of us," she continued. "Our time together was short, but we are grateful for the days we had with Oliver in my belly."

Herron wrote that Oliver had "taught us so much about the integrity of life, love and death" and had "filled our home and hearts with so much love and most importantly, optimism."

"The stars aligned to create Baby Oliver with a deep, meaningful purpose bigger than we'll ever understand. His body was small, but his legacy will always be larger than life to us," she added.

Herron ended her post on Wednesday by signing it "Mommy and Daddy."

"While our hearts are shattered beyond comprehension, we are comforted knowing that our son's soul only ever knew love and will not suffer in a body that wasn't built for this life. We'll never understand the cruelty of it all, but through the darkness, Oliver remains so so bright. We love you so much, baby boy. You will never be replaced. You are so perfect and awesome," she wrote.

Herron and Brown, who became engaged in May 2021, announced they were expecting their first baby together in September after going through in-vitro fertilization treatments.

Prior to her romance with Brown, Herron was a contestant on Sean Lowe's season of "The Bachelor," which aired in 2013. She also competed on "Bachelor in Paradise" in 2014 and 2016.