Dogs pass through the stages of pregnancy quickly. Gestation periods are comparatively short in dogs, which means that the pups develop rapidly inside the womb over a period of two-to-three months.
During the first month, the embryos travel to the uterine horns, usually around day 7, and the embryos are embedded in the uterine lining around day 16. The fetus begins to take shape by day 22, and by day 28 or 30 a veterinarian should be able to detect fetal heartbeats on an ultrasound.
Many dogs do not show any symptoms during the first three weeks of their pregnancy. Some symptoms to watch for during the first month are:
- Increased appetite
- Slightly enlarged nipples
- More affectionate behavior
- Clear vaginal discharge (around week four)
- Decreased physical activity
- “Morning sickness”
Fetal development moves quickly during the second month. Eyelids form by day 32 and toes are visible by day 35. The claws form by day 40, and the coat and skeleton follow a few days later (day 45). By day 50, an x-ray will reveal the number of puppies in the litter, and the bitch will start looking for a place to nest at day 58.
Signs of pregnancy in the bitch are much more obvious during the second month:
- Noticeably increased appetite
- Weight gain of 20-to-50 percent
- Increased urination
- Behavioral changes
- Clear, odorless vaginal discharge
- Enlarged, firm abdomen (days 45 to 50)
- Decreased appetite (day 45)
- Visible puppy movement in abdomen (day 50)
The bitch is ready to whelp by the start of the third month. Puppy development is almost complete around day 58, which means the puppies will begin to move into whelping position in the birth canal over the last few days of the bitch’s pregnancy.
Symptoms during the last few days of pregnancy in dogs:
- Waist will trim as puppies move into the birth canal
- Appetite loss around day 61 or 62
- Drop in body temperature 12-to-24 hours before labor
- Restless behavior
- Pacing, panting, shivering, or digging