You could also add an extra little insert card into the invitations of people you know have family and word it so as not to offend.
Make sure the invites are sent out with enough notice so that the parents have time to arrange sitters for the day or evening of the wedding day.
Some couples welcome a night out by themselves but be prepared for some people to be a little unhappy especially if they have young babies or if they are breastfeeding only. You will need to make some arrangements to accommodate these problems such as only inviting them to the evening etc.
Try to make sacrifices for those family members who you are close to who have babies or very small children.
If you are to have a small number of little guests attending, then why not accommodate your compromise by having a crèche set up in a separate area at the ceremony so that at least that part of your day will not be disturbed by them.
Remember, this is your special day and you want it perfect so if having children attending is not for you then go with it.
You will know that those who respect your decision and are in attendance are there for you and to help you celebrate your very special occasion.