I think it is important for those who suffered loss due to miscarriage or stillbirth to know they're not alone. I'm not really sure why a specific day was designated, or why the specific day was chosen.
For some,
October 15th is a day set aside to remember their loss. For me, it is difficult to post as most of the other infertility bloggers have (and not because I never suffered a loss). To me, October 15th is the day that I celebrate the birth of my daughter, Hadas, born after over 3 years of infertility, multiple failed IUI's and a failed IVF cycle.
Yesterday, Hadas (conceived with IVF) turned 15.

Here she is holding her little brother yesterday.

And last week, in our backyard.
Happy birthday, Hadas!
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P.S. I won't brag about her, but my mom did...