Heartbreak behind AFL star's post about birth of newborn twins

AFL star Gary Rohan has shared a heartbreaking post about the death of one of his twin girls just hours after she was born.

Rohan, who plays for the Sydney Swans, and his wife, Amie, welcomed their twin girls, Bella Rae and Willow Nevaeh, on Thursday morning.

The pair not only spent the past months preparing for the birth of their babies, but they also spent it preparing to say goodbye to one.

Just 11 weeks into the pregnancy, the couple were told one of their girls, who Amie nicknamed "Baby B", had anencephaly - a fatal neural tube defect with no cure.

Anencephaly affects the development of a foetus’s brain, skull and scalp. The babies with the defect sadly either die during birth or soon afterwards.

In an Instagram post announcing the birth of his "beautiful baby girls", Gary said they got to enjoy their short time as a family-of-four.

"The most perfect little souls we have ever laid eyes on, we feel so truly blessed to be your parents," he wrote on Friday.

"Amie, Bella and I soaked up every second we had with Willow, making as many lasting memories as we could all together.

"It's those little moments we know we will never get back, and we will forever cherish the time we spent as our little family of four, before our darling Willow grew her little angel wings.

"[It] was one off the hardest days Amie and I have ever had to deal with. It was a day full of many mixed emotions.

"Our little angel Willow, oh how much you taught us in your precious 5 hours here. ‘A life so brief, a child so small, you had the power to touch us all’."

The pair decided to announce the devastating news of Willow's condition on Instagram early on in the pregnancy in an attempt to raise more awareness of the defect and problems that may arise in pregnancy.

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Rohan called for anyone who shared his experience to reach out to him.

“There are going to be some really difficult days ahead but also many happy ones, and we want to share each and every one of those moments with you all," he wrote in an Instagram post.

“Talking about our situation with people has been our therapy, letting our emotions out has been the best thing for us personally.

“We would love for anyone who has been affected by anencephaly themselves or know of others affected by anencephaly to please contact us."