From my head on baby announcements
Regardless of the theme, though, certain information should always be included in baby shower invitations, such as date, time and location of the shower with names of the expectant mother and hostess, driving directions for out of town guests, and baby registry location. Some merchants having baby registries will provide you with cards to include with the baby shower invitations as an extra touch. Also be sure to include special instructions relating to meals and gifts, if necessary, and RSVP particulars. Make sure you give your guests enough advance notice by sending the baby shower invitations well in advance of the date. Guests will need enough advance notice to set aside time for the shower as well as purchase an appropriate gift.