Well the time has finally come!
I'm very happy for you and [NAME OF SPOUSE, ie. Jack] and I wish you both and the newborn the very best.
You did a great job in organizing your workload and delegating it to others during your absence, and we'll all pull together to make sure things get done.
{Please let me know when the moment gets closer so I'll have the inside track on the baby pool!}
Take care and see you soon.
Best regards,