How do i know my guinea pig is pregnant?

as aa said however you dont want the male in with the female when she gives birth as she comes in to season straight after, and back to back pregnancies can kill. you also need to rememebr to remove any male babies at 3 weeks old. pregnancies last approximately 10 weeks. and as said if you dont know you really shouldn't be breeding. did you no 20% of pregnancies result in mum and /or babies dying?

Every, about 14 to 18 days, the female goes through her cycle. This is when the mating can take place. The female will lie down on her stomach, with her rear slightly up. After the mating has taken place, you can expect the pregnancy to last about 3 months. Then the babies will be born. On average, there will be 2 or 3 baby guinea pigs in a litter. It does not really matter whether the father is present or not at the birth. Usually, he won't really care about it, and will stay away. But in some cases the father may choose to be helpful and clean the newborns. Don't be alarmed when blood comes out of the mother after all of the babies have been born. That's a natural part of the pregnancy. After about four to five weeks after the mating, the female will become more plump and round around the belly area. She will definitely be heavier. If you put the pregnant female on your lap, you can usually feel the babies moving around inside her.

Keep an eye on her if she is gaining weight she might be pregnant if she has already started gaining weight very gently feel her belly and you should be able to feel the babies inside her

IF you have to ask you shouldn't have them in the same cage.