[Self] What To Say?

I've got 2 lady friends who are going to give birth sometime this week. And I have no idea what is a socially approved / correct way to tell them. I mean ....

- Have a nice delivery ~ Sounds too much like "Have a nice flight" kan? And I'm a guy so this is totally wrong for me to say something like that
- Hope you have a good one ~ I cannot point out what's wrong with this but it feels terribly wrong
- Pray everything will be alright ~ Good intentions, but sounds morbidly out of place
- Heya, have fun with the kid! / Heard you're gonna burst this week g'luck! ~ I'll be lucky if they don't bonk me real hard on the head! Many many many times!!

So I guess here's what I'll do instead - just shut up and wait for them to tell me all went well, then visit them and googoo-gaga at those bundles of joy :)