Canine Pregnancy

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Most female dogs go into heat two times a year, some that have one to three cycles yearly. During the fourth day of the estrus cycle, which is marked by bleeding, eggs are released into the fallopian tubes and the fertility period begins. The estrus cycle in dogs can be anywhere between one to two weeks depending on the size, age, and breed of the dog.


After conception takes place, the fertilized egg travels to the uterus where the fetuses will develop. In the fourth week, the puppies’ spine and facial anatomy start to form. At this time, the uterus will also accumulate fluid for the fetuses’ protection. By the sixth gestation week, the sex organs, legs, and eyes are more distinguishable. At eight weeks, the fetuses are almost fully grown and starting to be repositioned for the birthing process. Finally, birth takes place around 56 to 63 days.

Litters in dogs vary from one to 12 puppies depending on the size and breed. In general, smaller dog breeds, such as Chihuahuas, tend to have one to three pups, while bigger dogs, such as Boxers, typically have six to eight puppies.


Signs are not very apparent the first weeks of pregnancy in dogs. Some dogs do, however, experience symptoms similar to humans, such as vomiting, decreased appetite, lethargy, and behavioral changes. Some of the more pronounced signs in canine pregnancy include:

  • Weight gain
  • Swollen abdomen
  • Swollen mammary glands
  • White nipple discharge


In the third or fourth week of gestation, veterinarians have three options in diagnosing canine pregnancy: run a blood test to check for hormones that are produced during pregnancy, palpate the dog’s abdomen for fetuses, and look for a heartbeat with an ultrasound machine. By the sixth week, an X-ray can give a more accurate idea of how many puppies there are and if their size might be a problem.

If puppies are not detected, the dog may have pseudopregnancy. This is a condition in which the body releases certain hormones and causes a “false” pregnancy. Although dogs with the condition are not actually pregnant, their behavior and appearance indicates otherwise. Pseudopregnancy in dogs clears on its own usually within one month, but it can recur.


Once pregnancy is diagnosed, your vet will schedule follow-up visits to monitor your dog’s health. You should discuss precautions, such as what type of preventative medication is safe to use, with your veterinarian.

As far as feeding goes, you can feed her puppy food the last couple of weeks of pregnancy to provide your dog with the extra nutrients that her body needs. This will also help prevent certain conditions, such as eclampsia (low blood calcium level), which can occur before birth or while nursing takes place due to nutrient deficiencies. It’s also helpful to feed small quantities throughout the day, as pregnant dogs have less space for food in their abdomen.

Some exercise is acceptable in the first couple of weeks of pregnancy as long as it’s not overdone. More rest will be necessary as the delivery date gets closer.


Although birth control injections and pills are available for dogs, spaying/neutering is the only way to fully prevent canine pregnancy.