question about possible pregnancy

Question
We have what we originally believed to be a female guinea pig. we wanted to get her a companion, so we purchased a female and they became friends instantly, doing everything together. the older one started to act motherly and caring for the baby, since she is older, but after almost a week, she started to act as if she were in heat, trying to mount the baby. we still had beleived she was a female, so we thought it might be just they way she was acting. but when we came in the room about 30 minutes later the baby was hiding in a corner and scared, when we picked her up we noticed soemthing stuck to her fur. it was white and felt like a hard plastic, although nothing like that had been in the cage. we tried to remove the white substance, but it is stuck and causes her pain if she tries to remove it. i looked up how to tell their sex and found that the bigger one is infact a male, but now im worried that the baby might be pregnant..how can i tell?

Answer
Hello Shelly,
one way of knowing if the female is pregnant is noticing that she will gain a lot of weight and be round in the tummy, she will also sleep more and will generally not want you to touch her stomach. Her personality will change a little bit and she will act different as well. After a few weeks you will more than likely know if she is pregnant or not as you can probably feel the babies move.