very pregnant female housed with another female

Question
I have two female guinea pigs. They have been housed together since I adopted one and purchased the other from what I believed to be a reputable pet store. Well turns out that she was pregnant when I got her. I have had her for 7 weeks now and it is apparent she is very pregnant.
My question for you is that is it safe for all involved (mom, other female and babies) if I leave the non pregnant female in the cage now and after birth? Should I separate them soon? They are just so bonded I don't want to stress either of them out, but I know I need to do whatever is safest for everyone.
I appreciate all you do for everyone who has questions and look forward to your advice.
Thanks so much for your time!
Melissa

Answer
There's no need to separate the two girls. Guinea pigs have a strong maternal instinct and will take care of any babies in the cage, regardless of who gave birth. Since the two girls are bonded it's best not to change anything. It's more stressful to have them apart and it's not necessary.

You will see a miracle of nature when you watch the two 'moms' care for the litter. Each will take turns bathing and caring for the babies. I have had sows that were not pregnant, but when babies were born in the same cage, would begin producing milk and nursing the pups.

I've always felt it was a help to a new mom to have an 'auntie' with her to help tend the children. So rest easy, everything will be fine and the babies will be happier and healthier because of it.