Her sister, Beth, experienced PP after the birth of her son, Leo and this is just the first in a series of 12 marathons she intends to run over the next year to raise money for APP.
You can read more about her story and donate to encourage this incredible effort over at her JustGiving page. In the meantime, Holly emailed us with a pre-race update:
"I have attached a photo of my first training run with my fabulous running partner Alaska. She is my cheerleader on my long distance training runs, and even at crawling pace when I'm on mile 17 of 18 she will give me that little helpful pull up the final hill!
Alaska is 3 and I've been running with her since she was a year old. She's helped me train for 10K and half marathon races in the past, and knowing that she needs to stretch her legs encourages me to put my kit on and go!
On Saturday I embark on Marathon 1 of 12. 5th of November, a poignant date for me as it is my nephew Leo's 3rd birthday. My sister has now fully recovered from her PPP after Leo's birth and they are celebrating his birthday in Disneyland Paris.
I will be thinking of her every step of my marathon journey and be thankful that she had the amazing support she did. Without that support I know things would have been different."
Please support Holly's amazing endeavour. Donate to sponsor her at JustGiving now.