"This is the last baby, the very last one. And there won’t be another."

Many mums say there’s a moment when it hits them that they’ll never have children again.

No matter how clear it seems that their family is complete, the emotions brought on by the final realisation that their last child has been born are unexpected and often overwhelming.

On Wednesday, one mum’s experience was shared on Love What Matters, a Facebook page dedicated to heartfelt stories about real people. In just a few hours, thousands of people had liked and shared the post, and hundreds had commented. Undoubtedly, this mum’s intriguing description of the complex blend of feelings that come with watching your youngest child grow up struck a chord with parents all over the world.

The original post, titled ‘The Last One,’ was written by Lindsay Ferrier in 2014 for her blog Suburban Turmoil.

“On the day that your last child is born, you’ll find yourself filled with a jumble of emotions,” she began.

"You’ll feel relief to have finally given birth, pride and joy in the healthy baby in your arms– and sorrow at the realisation that you’ll never again experience the primeval miracle of growing a baby inside your body."

Ferrier then explains the "strange brew of feelings" that engulf a mum when "every single one of your youngest child's firsts will also be your lasts".

When your last one is done with toys, nappies and bottles - so are you.

You also parent your last child in a vastly different way. "You won’t do a lot of the things with the last one that you did with your firstborn," Ferrier writes, "because you’ve been through it all before and frankly, most of it was completely unnecessary".

But watching the youngest grow up is painfully bittersweet. As you put them to bed and say goodnight, "you’ll hear a wistful voice in your head reminding you that [he or she] is the last one, the very last one, and there won’t be another".

"With each day that passes, the ribbon of childhood will feel like it’s unwinding too quickly before you and you’ll feel powerless to stop it," Ferrier writes.

"And as your youngest child abandons picture books for ones with chapters and leaves home for his first sleepover and demands that the training wheels be removed from his bicycle, you will be struck hard, repeatedly, by the fact that this most amazing time in your life is slipping away from you, bit, by bit, by bit."

Lindsay Ferrier's youngest son is now nine, and she has a 12-year-old daughter as well as two older step daughters.

Countless comments reaffirmed the sentiment of Ferrier's words, with one mum writing, "So true, but I feel very lucky to be able to mourn these things rather than yearn for them".

Listen: Libby Trickett on the unexpected challenges on motherhood. Post continues after audio. 

"Not everyone has the chance. Doesn't mean I don't feel a huge pang parting with all the baby bits though."

Another woman wrote, "I'm the youngest and I remember asking my mum, 'why are you crying?,'" but now says as a mum herself, she can relate.

It seems Ferrier has put words around an emotional experience that strikes parents so vividly, and in doing so, she's made a community of mums and dads feel far less alone.