Here's why:
* Gestation Period: The gestation period for dogs is around 58-67 days. This means a dog needs to be pregnant for almost two months before giving birth.
* Estrus Cycle: A female dog goes through an estrus cycle (heat cycle) where she is fertile. This typically happens twice a year and lasts for about two weeks. If a dog is not bred during that fertile period, she cannot get pregnant.
It's important to note: If a dog is showing signs of pregnancy again soon after giving birth, it could be due to a medical issue. It's best to consult a veterinarian to rule out any complications.