Your dog can get pregnant during the very first heat, or estrus cycle. Though most dogs experience estrus around 6 months of age, some small breeds can go into heat at four months old, so it won’t be long before your little princess is able to have pups of her own!

Dogs are pregnant for about 63 days, which is measured from the day that they ovulate (release their eggs) to the day that their puppies are born. Like people, dogs are pregnant for three trimesters, each about 21 days long.

Most dogs are first bred between the 10th and 14th day after the onset of proestrus. As long as the bitch will accept the male, mating every other day for a total of two or three matings is generally considered sufficient.

Dogs typically go into heat on average every six months, but this varies especially in the beginning. It can take some dogs around 18 to 24 months to develop a regular cycle. Small dogs usually go into heat more often — as much as three to four times a year.

What Signs Indicate That My Dog Is in Heat?

1. Swollen vulva.
2. Bloody or straw-colored discharge from the vulva.
3. Receptive to male dogs.
4. Excessive licking of the genital area.
5. Agitated, nervous, or aggressive behavior.
6. Urinating more frequently.
7. Change in tail position.

How to Calm a Male Dog when a Female Is in Heat

1. Keep the male away from the female until she is no longer in heat.
2. Put the dogs in separate rooms on opposite sides of your home.
3. Keep the female indoors and the male outdoors if space is limited in your home.
4. Board the male in a kennel until the female’s heat is over.

Erections can occur even if a dog is neutered, and full erection may result in the entire engorged penis and bulbus glandis extending outside of the prepuce. It’s important to note that a dog’s erection may last for just a few minutes or up to an hour or so.

“It’s a common play gesture.” It’s done by males and females, even by dogs that have been neutered or spayed, he says. “It’s a play behavior that dogs do because no one has told them it’s not acceptable,” Landsberg said. “It can become enjoyable or a normal part of the dog’s day, so it keeps doing it.

As puppies reach sexual maturity, they start to mount other dogs in sexual contexts. After they’re neutered or spayed, many male and female dogs continue to mount and even masturbate because they have learned that the behavior feels good.