Quick answer: The guinea pig gestation period is about 68 days, or just under 10 weeks. A normal pregnancy lasts anywhere from 59 to 72 days. Enter the mating date above to get the due date and the window to watch.
Guinea pig gestation period: how long are guinea pigs pregnant?
A guinea pig is pregnant for 59 to 72 days, with an average of 68. That is a long pregnancy for a small rodent. A hamster carries for only about 16 days.
The long wait has a purpose. Like chinchilla kits, guinea pig pups are born with fur, open eyes and teeth. They can run and nibble solid food within hours of birth.
| Days after mating | Weeks | Months | What it means |
|---|---|---|---|
| 59 days | About 8.5 | About 2 | Earliest normal birth |
| 68 days | About 9.5 | About 2.2 | Average length |
| 72 days | About 10 | About 2.4 | Latest normal birth |
Why do some sows give birth sooner?
Litter size makes the biggest difference. A sow carrying a large litter tends to deliver nearer the start of the window, and her pups weigh less. A sow carrying one or two pups often goes longer, and each pup is heavier.
Most litters have 2 to 4 pups. Each one usually weighs 100 to 120 grams (3.5 to 4.2 ounces) at birth.
Why does age matter so much for a first pregnancy?
This is the most important safety point for guinea pig owners. A sow’s pelvis has a joint at the front that must stretch apart to let the pups through. As she gets older, that joint stiffens.
A sow bred for the first time after about 7 to 8 months old is at real risk of a stuck pup. A C-section in a guinea pig is risky, and the mother often does not survive it.
Females can become pregnant from about 2 months old, so separate boars from young sows early unless a litter is planned. Talk to your vet before breeding any sow, and never breed an older sow for the first time.
How can you tell if a guinea pig is pregnant?
Look for these signs as the weeks go by:
- She gains weight steadily, and her belly widens into a pear shape.
- She eats and drinks more than usual.
- In the last few weeks, you may feel or see the pups moving.
Weighing her on a kitchen scale every few days is the easiest home check. For a firm answer, a vet can feel her belly or confirm it with an ultrasound or X-ray.
How to care for a pregnant guinea pig
- Keep her fed, not fat. Give unlimited hay and fresh water. Overweight sows face more birth problems.
- Keep up vitamin C. Guinea pigs cannot make their own, and a pregnant sow needs a steady daily supply from fresh vegetables or a vet-approved supplement.
- Lower stress. Avoid moving her to a new home or adding new cage mates late in pregnancy.
- Remove the boar. She can become pregnant again within hours of giving birth, so take him out well before her due date.
What is pregnancy toxemia?
Pregnancy toxemia is a serious illness that strikes in late pregnancy or just after birth. It is most common in overweight sows having their first litter.
Warning signs include not eating, being dull or weak, and a drop in activity. It can turn fatal quickly, so treat these signs as an emergency and see your vet the same day.
What happens when a guinea pig gives birth?
Birth is usually quick, and many sows deliver without anyone seeing it. The pups often arrive a few minutes apart, and she cleans them and eats the afterbirth.
Call your vet right away if she strains for more than about 20 minutes without a pup, has a green or bloody discharge with no pup, or seems weak. Guinea pigs hide pain well, so do not wait to see if things improve.
Caring for the pups
Pups nibble hay and pellets from day one, and they also nurse from the mother. Leave them with her until they are weaned at 3 to 5 weeks.
Males can mature very young, so move boars away from their mother and sisters by about 3 weeks old. Check the sex of each pup carefully, or ask your vet to help.
Guinea pig due date table
Find the mating date in the first column. The second column shows the 68-day average, and the third shows the normal window.
| Bred on | Due date | Normal window |
|---|---|---|
| Jan 1 | Mar 10 | Mar 1 – Mar 14 |
| Jan 15 | Mar 24 | Mar 15 – Mar 28 |
| Feb 1 | Apr 10 | Apr 1 – Apr 14 |
| Feb 15 | Apr 24 | Apr 15 – Apr 28 |
| Mar 1 | May 8 | Apr 29 – May 12 |
| Mar 15 | May 22 | May 13 – May 26 |
| Apr 1 | Jun 8 | May 30 – Jun 12 |
| Apr 15 | Jun 22 | Jun 13 – Jun 26 |
| May 1 | Jul 8 | Jun 29 – Jul 12 |
| May 15 | Jul 22 | Jul 13 – Jul 26 |
| Jun 1 | Aug 8 | Jul 30 – Aug 12 |
| Jun 15 | Aug 22 | Aug 13 – Aug 26 |
| Jul 1 | Sep 7 | Aug 29 – Sep 11 |
| Jul 15 | Sep 21 | Sep 12 – Sep 25 |
| Aug 1 | Oct 8 | Sep 29 – Oct 12 |
| Aug 15 | Oct 22 | Oct 13 – Oct 26 |
| Sep 1 | Nov 8 | Oct 30 – Nov 12 |
| Sep 15 | Nov 22 | Nov 13 – Nov 26 |
| Oct 1 | Dec 8 | Nov 29 – Dec 12 |
| Oct 15 | Dec 22 | Dec 13 – Dec 26 |
| Nov 1 | Jan 8 | Dec 30 – Jan 12 |
| Nov 15 | Jan 22 | Jan 13 – Jan 26 |
| Dec 1 | Feb 7 | Jan 29 – Feb 11 |
| Dec 15 | Feb 21 | Feb 12 – Feb 25 |
Frequently asked questions
How many months is a guinea pig pregnant?
A little over two months. The average is 68 days, which is about 9.5 weeks.
How many babies do guinea pigs usually have?
Usually 2 to 4. Litters of one or five or more can happen. Larger litters tend to be born a little sooner.
Can a guinea pig get pregnant right after giving birth?
Yes. A sow can conceive again within hours of giving birth. Remove the boar before her due date to give her body time to recover.
Is it safe to breed a 1-year-old sow for the first time?
No. By then her pelvic joint has usually stiffened, and the risk of a stuck pup is high. Ask your vet before breeding any sow, and avoid a first litter after about 7 months old.
Do guinea pigs give birth at night?
They can give birth at any time, and often while nobody is watching. Check on her first thing each morning once she reaches day 59.
How does a guinea pig pregnancy compare with a rabbit?
A guinea pig carries more than twice as long. A rabbit is pregnant for about a month, as our rabbit gestation calculator shows, and her kits are born blind and hairless.