Mourning an unimaginable loss.

Bachelor Nation first met Sarah Herron on Season 17 of “The Bachelor,” and she returned to our screens for Seasons 1 and 3 of “Bachelor in Paradise.”

Since her time on the Bachelor Nation shows, Sarah has been extremely open with fans about her journey with fertility, egg freezing, and pregnancy loss.

In September, after many high highs and low lows of the IVF process, Sarah revealed that she and her fiancé Dylan Brown were finally expecting a baby boy.

On Wednesday, Sarah took to Instagram to share the tragic news that their baby boy passed away shortly after he was born prematurely at 24 weeks.

Alongside heartbreaking photos with their son, Sarah wrote, “On January 28th, at 24 weeks old, our beautiful son Oliver Brown was born. 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.”

In the carousel of photos, Sarah shared special moments from her pregnancy, including swimming with sea turtles, a trip to the beach, and cuddling with their dog.

The series of photos ends with an image of Dylan kissing Sarah’s forehead as she cries in a hospital bed.

The Bachelor Nation star went on, saying, “Our time together was short, but we are grateful for the days we had with Oliver in my belly. He has taught us so much about the integrity of life, love and death. Oliver 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.”

Sarah concluded her emotional post, writing, “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. Love, Mommy and Daddy.”

Sarah’s fellow Bachelor Nation stars like Catherine Giudici Lowe, Raven Gates Gottschalk, Jade Roper Tolbert, Becca Tilley, Jared Haibon, Natasha Parker, Kendall Long, and so many more shared their condolences and love in the comments of her post.

Sarah took to her Instagram Stories to thank everyone for the love and support. She wrote, “Thank you all so much for the messages. I think I’ve read all 8,000+ of them overnight. It helps to hear your stories.”