Is my cavy pregnant

Question
On December 17,2006 I put my then, 6 1/2 month old, female guinea pig with my then, 9 month old, male guinea pig with hopes to breed them. My question is why my female doesn't appear to be pregnant yet, and if she is, is it normal for my male to continue to mate with her as if she is in estrous. I am also very concerned about her health in regards to getting pregnant beyond the 5-8 month time frame (for females to get pregnant). I am not sure if I should separate my piggies, but I also know that they will be very upset if they are separated from each other.      Thank you.  

Answer
Yes, it is normal for mating to continue through her pregnancy. There will be a lot of questions you will ask yourself when you find out she is pregnant, because they are not careful! :)  They will run and jump into things and it will hit their belly and they will fall backwards. I was so scared that she was going to hurt her self when mine was pregnant, but she knows what she is doing:)
If there is the -slightest- chance that she is over 7 1/2 months old, you need to keep them separate. Female guinea pigs over the age of 8 months should not be bred. If they are over 8 months and have never had babies before, it is life threatening.
At age 8 months, piggies who have not had babies before will not be able to deliver their baby because the pelvis bone will be closed. In this case cesarean section is inevitable, and very dangerous.
As far as telling if she is pregnant, other than inactivity and excessive water drinking, her belly will become obviously pregnant because it will be twice her size, and bouncing around with active babies by 60 days. The only indication of birth is around 70 days, 48hrs before she gives birth, her pelvis bone (between her legs) will spread to an obvious 1.5 inches. From that point on it is close to show time.
If she is pregnant, make sure to take extra good care of her. Give the mommy veggies high in vitamin C such as parsley and cabbage. Before the mother has her babies, you need to remove the daddy. She will give birth on her own, and involvement by you is a bad idea. The only time you should get involved is if she is screaming or pushing for over 10 minutes without the result of a baby. In these cases she should be rushed to a local vet. Cesarean sections are not healthy and very dangerous.
The babies stay with mommy for 3 weeks.  At this time, mommy, baby girls, and baby boys should be separated from each other. The baby boys are sexually mature at age 3 weeks, so they are able to get mommy or sissy pregnant, so separation is important. They should stay in your care for another 3-4 weeks before finding a home.
Good luck! Let me know how it goes, and if you have anymore questions!