Why haven't my female dogs gone into heat by age one? Is it normal?

She could still go into heat at any time. Some dogs go into heat later than others, although smaller breed dogs tend to go into heat by a year of age. It could also be that she has gone into heat, but it was a silent heat so you didn't notice any signs of it. I'd have her checked out by a vet to be safe. Best of luck.

It is unusual that Maria hasn't gone into her first heat at her age, and it's possible that she has had a heat but it was a silent heat. I'd recommend a check up with the vet for this problem. It would be rare if she was born without a uterus, but it could be possible. Only a vet can diagnose this. I'd make an appointment for her this week. I hope this helps!

Typically dogs do have a heat every six months, but it could be Cleo had a heat and it was a silent heat. Silent heats are when the dog shows no outward signs of being in heat. You can have her checked out by a vet to be safe. Best of luck.

There first hear cycle can often be missed and be a silent heat since the changes in their body are new. It is common to miss it. At her age a second should be approaching soon. The lager the dog, the later and farther between the cycles can be.

Female dogs don't actually stop having [heats](https://www.petcoach.co/article/anatomy-and-function-of-the-reproductive-system-in-dogs). This is because as they get older, they do not always show the external or behavioral signs that they are actually having a heat, this can sometimes be referred to as a ‘silent heat.' It is important to remember that even though your dog may not be showing signs of being in season that she could still get pregnant if mated by an intact male dog. Ideally, you should consider having her [spayed](https://www.petcoach.co/article/spaying-ovariohysterectomy-the-benefits-in-dogs). There may also be an undiagnosed hormonal disease or ovarian disease present that stopped her cycling. In order to make sure it is not a serious condition you should have her checked by a veterinarian. It is possible that it is a harmless reason, but it is also possible that there is a serious underlying condition.

You are correct that Panda could start going into heat suddenly, as female dogs can start their first heat any time after six months. If you don't bland on mating Panda, I would get her spayed as soon as possible.

Normally, bitches in season do not behave very differently from their usual selves. Since it is her first heat, there may be a problem showing up that was not evident before her reproductive organs became active. Or, it could be something else altogether. Your best bet is to take her to the vet for a thorough exam to determine an accurate diagnosis and, if necessary, appropriate treatment plan.