how long till my cat gives birth?

My pretty girl khloe is expecting and I need to know how much longer it might be till the kittens arrive she has milk in her nipples and has had a little bit of discharge I've noticed this for 3 or 4 days now so can someone tell about when labor might start?? Thanks!!

We have a good collection of articles in the Cat Health section which you can access by scrolling up to the brown bar, clicking on Articles, and then choosing the Cat Health section and scrolling through the choices.  To make this super easy for you, I am copying the links regarding birth, delivery and newborns for you here.  After reading this information, let us know if you have any more questions.  And good luck with your approaching new arrivals.

Birth, Delivery and Newborns

How to Tell if My Cat is Pregnant?
Cat Pregnancy
How Do I Know When My Cat Will Give Birth?
Pregnant Cat? What to Prepare For the Birth
Help! My Cat is Having Kittens!
Premature Kittens
Post-Birth Complications in Cats

are these signs of labor?

and this the first one is discharge and this one is what her nipples look like