How weird is it to send out a baby's christening invitation when she hasn't even been born yet?

I just got an Evite from a friend for her daughter's christening on the weekend of Thanksgiving. Her daughter's DUE DATE is three weeks away!!!! This just weirded me out a bit and I haven't been able to find out anything about such things on the etiquette of this event on the internet so I was hoping I could get some insights on here... I mean, there are cultures who don't even BUY things for the baby before it's born out of superstitious that it's tempting evil spirits to harm the unborn child... we're not from those cultures, but still.... isn't it just a little GAUCHE to send out an invitation to something for someone who isn't even born yet??? Just curious! Thanks!