How to tell if my female is pregnant
Sometimes it's not easy at all to tell if the female is pregnant or if you just fed her too much. If females expects only a few babies, sometimes only 1 or 2, it's possible you won't notice the pregnancy at all - till the time babies are born. It of course depends on how experienced you are with degus.
But usually you can notice that female's belly is not just bigger but also hard to touch (but touch her only gently or you could harm babies). And in the third (last) month of pregnancy you can even see babies moving in belly when female lies and rests.
About in the day of delivery, female starts to collect materials for nest, like tissues or whatever soft she finds in the cage, so you should provide something. Father also helps with this. Right before delivery she sometimes lies on her back and looks strange and tired.