Jo Crouch's daughter Holly-Ann died when she was just 15 weeks old.
Jo went to sleep with her baby in her bed and when she woke up, Holly-Ann had died.
"For years, I blamed myself," said Jo, of Cheviot Road, Durrington.
"No-one knows what causes sudden infant death. There's a lot of research into it but it costs a lot of money and there simply isn't enough funding.
"I have come to terms with the fact I will probably never know what caused Holly-Ann's death but I will always wonder."
Now, 12 years after her daughter's death, Jo has organised a sponsored walk in memory of Holly-Ann and to raise money for the Foundation for the Study of Infant Deaths (FSID), which helped her when her baby died.
The Mile in Memory walk will go from the Lido to George V Avenue and back on May 22, from noon to 3pm.
More than 50 people are expected to attend, including many "angel mums", as Jo calls them.
She said: "An angel mum is someone who has lost a child like me.
"Doing something together like this is comforting because you don't feel so alone."
Jo, 34, who now has five other children and a step-son, also plans to become a helpline assistant for FSID and has arranged a charity skydive in September.
For more information, request to join the Facebook Mile in Memory event page or join the walk on the day.
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