Track guinea pig (cavy) pregnancy with due date prediction and week-by-week milestones. Covers the 59-72 day gestation, pup development, nutrition, and breeding safety.
Guinea pig (cavy) gestation averages 63-68 days, with a normal range of 59-72 days. This is notably longer than most rodents, resulting in highly developed pups born with fur, open eyes, and the ability to eat solid food within hours. Litter size typically ranges from 1-6 pups, with 2-4 being most common, and litter size directly affects gestation length — larger litters tend to deliver earlier.
A critical safety consideration: female guinea pigs (sows) must have their first litter before 7-8 months of age. After this point, the pubic symphysis fuses permanently, making natural delivery of the relatively large pups extremely dangerous or impossible, requiring emergency C-section. This is unique among common pets and is a vital breeding consideration.
This calculator tracks your guinea pig's pregnancy day-by-day, predicts the delivery date, shows developmental milestones, and provides stage-specific nutrition recommendations. Proper care during the 9-10 week pregnancy ensures the health of both mother and pups.
Accurate tracking of guinea pig pregnancy ensures timely nutrition adjustments, proper veterinary care, safe breeding age management, and preparation for delivery. The unique pubic symphysis concern makes age-aware breeding planning especially important. This guinea pig pregnancy calculator helps you compare outcomes quickly and reduce avoidable mistakes when making day-to-day care decisions. Use the estimate as a planning baseline and confirm final decisions with a qualified professional when risk is high.
Due Date = Breeding Date + 65 days (average). Normal range: 59-72 days. Smaller litters (1-2): tend toward 68-72 days. Larger litters (4-6): tend toward 59-63 days. CRITICAL: First litter must occur before sow reaches 7-8 months — pubic symphysis fuses after this age. Pup birth weight: 60-115g average, larger with smaller litters.
Result: Expected delivery: ~March 21, 2026 (day 65, range: March 15-28). Safe for first pregnancy (under 7 months).
A 5-month-old sow bred January 15 is within the safe window for a first pregnancy. Expected delivery around March 21 (day 65). Larger litters may deliver earlier. Increase vitamin C to 30-40 mg daily. Pups will be born fully furred with eyes open.
This cannot be overstated: if a female guinea pig has not been bred before 7-8 months of age, she should NOT be bred. The pubic symphysis — the cartilaginous connection between the two halves of the pelvis — ossifies (turns to bone) and becomes rigid. During delivery, this joint must separate to allow passage of the relatively large pups. When fused, natural delivery becomes impossible, resulting in dystocia that is fatal without surgical intervention. Plan breeding before 6 months of age to ensure safe first deliveries.
**Weeks 1-2:** Embryos implanting. No visible changes. Maintain normal diet plus extra vitamin C. **Weeks 3-4:** Embryos developing rapidly. Slight weight gain. Begin offering alfalfa hay for calcium. **Weeks 5-6:** Pups developing organ systems. Sow becoming visibly larger. May feel pups moving. **Weeks 7-8:** Rapid fetal growth. Sow noticeably large. Pups developing fur, opening eyes in utero. **Week 9-10:** Final growth, positioning for birth. Sow may be enormous with large litters. Nesting behavior. Birth imminent.
Guinea pig labor is often quiet and quick. Signs: widening of the pelvic gap (feel gently), hiccup-like movements from the sow, stretching and rearranging bedding, possible decrease in appetite 12-24 hours before, and a hunched sitting position during contractions. Most deliveries take 15-45 minutes for the entire litter. Each pup arrives in its sac, which the mother breaks open. Call a vet if: active straining for >20 minutes without a pup, or delivery stalls for >30 minutes between pups.
Average 63-68 days (about 9-10 weeks), with a full range of 59-72 days. This is much longer than hamsters (16 days) or mice (19-21 days) because guinea pig pups are born fully developed (precocial) — furred, eyes open, teeth present — rather than hairless and helpless.
After 7-8 months of age, the pubic symphysis (the cartilaginous joint connecting the pelvic bones) fuses and can no longer separate during delivery. Guinea pig pups are relatively large, and without pelvic expansion, they cannot pass through the birth canal, resulting in dystocia (obstructed labor) that is fatal without emergency C-section.
Typically 1-6 pups, with 2-4 being most common. Larger litters have shorter gestation and smaller individual pup sizes. First litters tend to be smaller (1-3). Pups weigh 60-115g at birth and can double in size within 2 weeks.
Gentle handling is fine and important for socialization and health monitoring. Support the entire body when lifting, never squeeze the abdomen, and limit handling in the last 2 weeks to reduce stress. Daily weighing helps track health.
Unlimited timothy hay, alfalfa hay (for extra calcium), high-quality pellets with vitamin C, and fresh vegetables daily. Increase vitamin C to 30-40 mg daily (from the normal 10-25 mg). Provide extra water as pregnant sows drink more.
Pups nurse for 2-3 weeks but eat solid food from birth. Males must be separated by 3 weeks (21 days) to prevent pregnancies — male guinea pigs reach sexual maturity by 3-4 weeks. Females can stay with the mother longer.