I would like to say upfront that I am NOT an advocate for breeding. There are many animal rescues around the world that have dozens of guinea pigs waiting for a second chance in life....and it really is immoral to still breed your own pigs with so many homeless ones out there.
This is a reference/info page for people with pigs who may have had accidental pregnancies, in which case you need to read up on taking care of pregnant mothers and the babies.
Risks and dangers to pregnancy:
There are several risks to pregnancy. The mother may have a miscarriage, there may be complications that result in the death of both mother and child. On the other hand, what if the mother dies, who is going to raise the baby pigs? Baby guinea pigs are very fragile and vulnerable, ALL the responsibility will fall onto your shoulders to hand raise them.
An average birth will be 2-4 babies. If it is not your sow's first pregnancy, the litter will be bigger-up to 6 babies. Can you commit to and handle 6 more guinea pigs in the house? You will need to buy/make new and bigger cages to house them, pellet/shavings demand will undoubtedly go up, not to mention potential vet bills. Again, I strongly discourage breeding your pigs...this is to be responsible both for your pig and yourself.
If you have an accidental pregnancy, it is important that you have a well-known vet whom you can contact during emergency hours. You don't know what may come up during the pregnancy, and if something goes wrong, the worst thing is you frantically calling the directory for a nearby vet clinic.....tape your vet's contact info. somewhere big and clear near the cage, so you know how/where to look for help, and your family members are well-informed.
When the mom is getting big....
When the female is pregnant, she will be taking in significantly more water and food, and you need to supply her with TWICE the amount of vitamin C as normally. Make sure she is not living with any fertile males. It is usually fine to have her live with other females, you want your piggy to feel as normal as possible. No stress! Observe the mom-to-be closely to make sure she is healthy, eating normally and not in any pain or discomfort. She will start to grow and "balloon" a few weeks into the pregnancy. Limit the times you pick her up or handle her, in case you injure the babies inside.
When the mom is going to give birth....
It is hard to predict exactly when she is going to give birth, as you do not know the exact day of conception....I apologize that I'm not very experienced in this area, but do go HERE to Peter Gurney's website, or visit Petergurney.com and click on "The A to Z of guinea pig" on the left sidebar, where there are pages explaining every stage from pregnancy to birth to hand raising to what to do in emergency situations.
Unlike hamsters or rats, prospective piggy moms do not do much in preparation for their birth. They do not build nests. Perhaps they will retreat to a quiet place. If you are lucky enough to be present while the mommy is giving birth, sit by quietly. The sow will go into labor...contractions...She will sit there and bend over to her genital area as she tries to pull out the babies with her teeth. Don't worry, she's not going to nip her own babies, by "pull out", she will lock her incisor teeth around the incisor teeth of her young, and gently pull them out. When the babies are born, they will be enclosed in a sack, which the mother will promptly break open so the baby can breath. If 2 babies have come out at the same time, the mother will focus all of her energy on one baby, this is when your intervention is crucial: pick up the other baby still enclosed in the sack, and pierce it with your fingernails. Peel the sack away from the baby, and turn it over in your hands a few times to help the air flow into his lungs, then return the baby back to the mother. Please do not leave the father in the cage when/after the mother has given birth, because she will become immediately fertile after birth, and if the male gets her pregnant again, it will be extremely hard on her body.
There should not be much blood, and the mother will lick herself clean after the birth.
After the mommy gives birth:
When the mother has cleaned up all of her offspring, they may gather around their mommy and start to suckle from her. This must be one of the most heartwarming moments: watching baby piggies suckle milk from their mommies. If you are nearby, please be very quiet and avoid any sudden movement. The babies are able to eat solid pellets and drink water as they are fully developed upon birth. Please make sure they can reach the water bottles!! Provide mother and baby with plenty of warmth and comfortable towels.
Complications during birth:
Pregnancies can be risky on the mother and the baby, so it is best if you are present during the time in case of emergency. If the mother seems to be exhausted, if there is a great loss of blood, if the mother is bending over again and again with no outcome or is shrieking with pain....TAKE HER TO THE VET RIGHT AWAY!!
If the mom died....
This will be very tragic and devastating for you...but even more so for the babies, who need their mother's milk, warmth and nourishment.
If you are (extremely) lucky enough to know someone who's guinea pig has also recently given birth, you can put your newborns with that mother as foster babies.
Provide warmth: If you need to raise the guinea pigs by yourself, you will need to keep them in a cozy cage, with plenty of blankets. It is best that you give them a warm water bottle to snuggle up to which will imitate the warmth of the mother. You can also have a lamp as a heat source, but make sure the babies can move away from the lamp if they feel too warm.
Feeding: DO NOT syringe feed baby pigs, their little bodies are unable to synthesize breathing and suckling and the food can easily get into their lungs. You need to feed them both mashed up pellets, and milk. You can use powder milk formulated for babies or goat's milk. It is best that the milk is warm, because the mother's milk will be warm from her body. Pour the milk into a small teaspoon and hold it under the baby's mouth. You can do the same with dissolved alfalfa pellets.
You will find that the babies will not eat a lot in each time, but they will eat frequently. Do not try to force more food into them in an attempt to decrease the frequency of feeding. You should feed the babies at least 4 times a day.
Water: Hold the water bottle to their mouths, they should be able to figure out that when they push their tongue up, water will come out.
Stimulate to defecate: if the mother is present, you will notice that in taking care of her young, she will repeatedly lick the genital areas of her young to stimulate them to defecate. You can imitate the mother's tongue with a damp cotton swab, just rub it against the baby's genital area in a circular motion 3 or 4 times a day.
Guidance from grown ups: If you have any adult females, (or even males) put the babies with them, as they can provide some warmth for snuggling, and also serve as guidance. Baby piggies are very adept at learning from their environment and imitating any grown ups. They should soon learn where the food bowl/water bottle is and how to eat/drink from it. Having adults around will also give them a sense of security.
Guinea pigs will be weaned by 3 weeks so please separate males and females by then.