This can be a delicate subject in a game, so make sure it comes up naturally in the flow of events and all your players are prepared for it.

Transcript

Padmé: I've been dying to know how your audition went. I tried to get Pete to find out, but he said you were being irrationally evasive. So...?
{beat}
Anakin: We have to talk about our future... Padmé.
Padmé: Who? Oh, right.
Anakin: I've been off saving Palpatine and uncovering a Sith conspiracy. What have you been doing?
Padmé: I've been working on my thes... oh, wait... um...
Padmé: There's this... thing I've been busy with.
Anakin: That sounds interesting. What is it?
Padmé: Well, I've been really worried about it and... feeling a bit sick.
Anakin: You're not...? Are you...?
Padmé: No. That is... yes, I think so?
Anakin: You're having a baby?
Padmé: I'm having a baby?
Obi-Wan: She's having a baby?
Padmé: Well, actually—
C-3PO: She's having a baby! Yay!
R2-D2: Congratulations, Padmé.
Padmé: Um... okay.