You may want to try some sub-reddits on Reddit. If you are familiar with Reddit, you could try posting on /r/parenting. Although most posts on /r/parenting are for parenting advice, it is visited by a lot of parents on a daily basis. That may be one.
Other possibilities would be mommy specific forums or reaching out to popular mommy bloggers / twitter and ask them if they can help out with this. Some may oblige by sharing it with their followers.