How to Tell if a Guinea Pig is Pregnant: Quick Guide

Part 1: Signs of Estrus in Guinea Pigs

When a female guinea pig is in heat, you might notice a milkywhite discharge from her genital area. She may also seem more restless and anxious than usual, even crying out without apparent reason. Gently stroking her upper rump can trigger excitement. If kept with males, the male guinea pig might attempt to mount the female.

One reliable method to determine if a guinea pig is in heat is the presence of a mating plug. After mating, the female will expel a milkywhite plug, which is a result of the male's semen. This plug serves to seal the female's vagina after breeding, enhancing the chances of successful mating. Typically, when a mating plug is found, the success rate for mating can be around 85%.

However, it's important to note that guinea pigs are nocturnal and often mate at night, so the mating plug may be expelled during the night and eaten by the female, making it difficult to observe in the morning.

Part 2: Indicators of Pregnancy in Guinea Pigs

Owners can also use the presence of a mating plug as an indication of pregnancy. The expulsion of a mating plug suggests that the guinea pig has mated and is likely pregnant, though the plug might be eaten and go unnoticed. Another way to determine pregnancy is by weighing the female guinea pig. After pregnancy, her weight will significantly increase. She may show a marked weight gain, increased appetite, and a gradually expanding belly, which are clear signs of her late pregnancy. At this stage, owners can gently feel her abdomen to check for any firm lumps, which would confirm that she is pregnant for over 25 days.

Dr. Oxygen Pet Tips: The gestation period for guinea pigs is between 68 to 75 days. It's essential for owners to calculate the expected due date well in advance to prepare for the upcoming birth.