However, the week before a sow is about to deliver a litter, a slowly widening separation of the pelvis develops just in front of the external genitalia. This separation reaches slightly more than 1 inch in the hours just before delivery. This separation of the pelvis does not develop in females that are bred for the first time after 7 months of age, creating an impossible and tragic situation. Delivery of the young is not possible and a cesarean section must usually be performed to save the life of the sow and her babies. Litter sizes range from 1 to 6 young, with an average of 3-4.
Litters resulting from the first breeding are usually very small.
Abortions and still- births are common with guinea pigs throughout their breeding lives. The young are born relatively mature. They are unusually large and fully furred, and can walk about. They also have teeth and open eyes at this time. Even though newborn guinea pigs can eat solid food and drink water from a container, they should be allowed to nurse their mother for at least 2 weeks.