guinea pigs labor

Question
How long should it take for a mom to push out her baby once it has started coming out?

Answer
The babies should be delivered about 5 minutes apart, so each baby should come out in less than 5 minutes.  It really doesn't take long for the babies to be delivered.  The whole birthing process should only take about 30 minutes, so if it is taking longer than that, there is definitely a problem.  Hopefully you are asking this question just to be prepared, which you should be.  I strongly suggest doing A LOT of research before breeding, and especially the delivery, because you need to be completely prepared for the birth.