An unspayed, female guinea pig who has been with unneutered male guinea pigs and is gaining weight might be pregnant, or she might have a medical issue.
Q: How can I tell if my guinea pig Angel is pregnant? We just got her two weeks ago, but as the days go by she looks like she is gaining weight. We also have a boy but when he tries to do something with her she kicks him and starts squealing and tries to get away from him. We bought them a little hut for them to be cozy in, but if she is in there she will not let him in and once he gets in there she is not happy and storms out of the hut. When he is in the hut she will not go in until he gets out. Is this normal? I just want to know if she is going to have babies. I don’t want to be surprised. I want to make her comfortable before she has babies.
A: Yes, your guinea pig can be pregnant. If she is not spayed and has been with male guinea pigs before you took her home, she very likely is pregnant. The gestation period in guinea pigs is relatively long for a rodent, approximately 60 to 70 days.
If she was bred in the last two weeks by the male you have, you would not yet see changes in her appearance. If she is indeed has a change in her appearance because she is pregnant, breeding had to have occurred before you got her.
If she is pregnant, you must separate her from any other guinea pigs you have, including the male, for two important reasons. First, it is possible that she could be bred again almost immediately after giving birth. Unless you want more baby guinea pigs, you should separate her from any male guinea pigs before this litter is born. The other reason not to have other adult guinea pigs near the new babies is to prevent the possibility of other adults injuring or even eating the young.
It is in your pet’s best interest for you to visit a veterinarian that is well-versed in guinea pig medicine. Weight gain can be caused by reasons other than pregnancy, and these can be serious diseases. Your veterinarian can examine your guinea pig to determine if she is pregnant.
Also, it is highly recommended that guinea pigs be first bred before they are 6 to 8 months of age, otherwise their pelvic symphysis will fuse. If this structure fuses before a guinea pig delivers her first litter, there may not be enough space for the guinea pig young to be born. If this occurs, likely both the mom and babies will die unless a Caesarian section is performed.
If your guinea pig is older than 6 months and this is her first litter, you really should visit your veterinarian — your guinea pig and lives of those in her litter may depend on it.
A guinea pig-knowledgeable veterinarian can examine a guinea pig to determine if she is pregnant.