After losing her newborn, this mum did something amazing for her...

The sheer strength and courage of our fellow mums around the world never fails to impress and amaze us, and the story of what Sarah Rieke did for her best friend Lauren Casper will surely touch your heart today.

The friends, both from the US, have had a taste of viral stardom this month after sharing the incredible story of how they bonded through a bittersweet time of joy and tragedy.

Lauren and Sarah were delighted when, back in 2012, they were both preparing to welcome children into their lives – Sarah was pregnant with a daughter, while Lauren was in the process of adopting a baby girl of her own.

If you visit laurencasper.com (and many other places) you'll find a post about something special I was able to give my friend after Evie died. So many people are saying such kind things about this story, which is just so nice. But I just have to say something ... I'm not a saint. At the time I didn't feel like what I did was especially special. It just felt like a solid, logical conclusion to donate that "liquid gold" to my friend's brand new baby who had never been fed breast milk. It was a privilege, really, to do that for my dear friend and her precious daughter and to think about them and pray for their family as I pumped. Arsema was such a smiley, spunky, early milestone kind of baby ... I like to think I helped contribute to that Maybe there aren't a lot of people who would have made that choice after losing their daughter, but if roles were reversed, there's not a doubt in my mind Lauren would have offered the same to me. I am grateful to have her in my life ... @lcasper1 If you tune into the #heartlessons #podcast this week, you'll be able to hear a little more about our friendship journey. I promise there's more to it than breast milk (Link in profile or search heart lessons via iTunes) #friendship #thankful #momlife #infantloss #adoption

A photo posted by Sarah (@sarah_rieke) on Jun 1, 2016 at 11:04am PDT

Matters took a turn for the tragic, however, when Sarah learned during her 20-week scan that her baby would not survive for long outside of the womb. Indeed, Baby Evie passed away just four hours after entering the world.

In the midst of her grief, and with Lauren after welcoming daughter Arsema into her new home, Sarah did something astonishing: she offered to breastfeed Arsema with the milk her body was still producing for Evie.

Writing about this beautiful gesture from Sarah, Lauren told Today.com: “Sarah was longing to do something meaningful and, in a way, her feeding my daughter helped heal a tiny piece of her broken heart.”

On her own website, Sarah wrote about the experience in detail, in a post entitled ‘On Feeding My Friend’s Daughter When I Couldn’t Feed Mine’.

In the piece, Sarah is incredibly modest, as she writes: “Pumping milk for Arsema after Evie passed away was a blessing for me. It was good for me to sit and be still and take the time to think and reflect on Evie’s life and pray for Arsema’s future…Even though readers are commenting on what an amazing woman I am for making that decision, it really felt so normal. Logical, really. A blessing, certainly, on both sides. But maybe not as saintly as others seem to think.”

One thing is for sure: these women and their families are beyond lucky to have each other.