A dog pregnancy lasts about 63 days, or roughly nine weeks, with a normal range between 58 and 68 days. This variation occurs because the exact date of mating does not always match the exact date of conception. Female dogs can store viable sperm inside their bodies for several days before their eggs are fertilized. Additionally, the litter size and breed can influence the timeline when asking how long are dogs pregnant. For instance, mothers carrying larger litters often give birth a few days early, while small litters with only one or two puppies may cause a slightly longer pregnancy.

Week-by-Week Development

• Week 1 (Days 0–7): Fertilization occurs high up in the oviducts after breeding.
• Week 2 (Days 8–14): Embryos travel down into the uterus for spacing.
• Week 3 (Days 15–21): Implantation happens into the uterine wall, which supplies life-giving nutrients.
• Week 4 (Days 22–28): Spinal cords develop and faces take shape. A vet can feel the grape-sized embryos.
• Week 5 (Days 29–35): Toes and claws form as embryos look like tiny puppies. Weight gain begins.
• Week 6 (Days 36–42): Skin pigment develops and internal organs grow. The belly noticeably swells.
• Week 7 (Days 43–49): Fur starts growing and skeletons begin hardening. Hair loss around her nipples occurs.
• Week 8 (Days 50–57): Puppies move actively inside the womb. Milky fluid may leak from her nipples.
• Week 9 (Days 58–65): Nesting behavior starts as the mother prepares a safe spot to give birth.

Key Veterinary Milestones

• Day 21–25: Relaxin blood test can confirm pregnancy.
• Day 25–30: Ultrasound confirms vital signs and fetal heartbeats.
• Day 45+: X-rays count the exact number of puppy skulls and spines.

Signs of Upcoming Labor

• Temperature drop: Her body temperature falls below 99°F (37.2°C) roughly 24 hours before labor.
• Appetite loss: She will likely refuse food or vomit right before whelping starts.
• Restlessness: Shivering, pacing, panting, and scratching at blankets are common signs of early labor.