Why isn't my 3-year-old female dog going into heat? Is it serious?

She may have ovarian cysts or other hormonal problems that keep her from cycling properly. I suggest you take her to a veterinarian who can give her a proper breeding exam, take some blood to check her hormonal status and do some vaginal cytology to check her cycle status. He can also do an ultrasound exam of the ovaries. Once he has all those results he can make a plan on how to start her cycle, ie get her in heat to be bred.

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.

Sometimes female dogs do not come into heat until they are 2 years old. This would not be abnormal. If you would like to know whether Gypsy is in heat now, I suggest you take her to your vet for an exam. The vet will take a vaginal swab and look at the cells under the microscope and can tell you exactly whether she is not cycling, in pre-estrus, or estrus.

Yes, it can be normal. Often times though, they have gone into heat, you just didn't notice. Some dogs keep their vulva clean so you don't notice any bleeding. If you are worried then I suggest you take her to your vet for a breeding soundness examination.

It may be that your male is still very young and doesn't know what to do yet. Keeping them together during your female's heat may help get him interested in trying to figure it out. However if he still doesn't show any interest, having both him and your female examined by a vet or theriogenologist (reproductive specialist) to make sure everything is OK is best.

Large dogs such as Tasha often do not come into heat until 10-15 months old so I'm not concerned yet. I like to have them be at least two years old and have their hips checked with an X-ray for hip dysplasia before breeding. German Shepard Dogs can have bad hips that can be passed on to the puppies so I always want to make sure both parents have good hips before breeding. Generally I recommend the female dog only have one to two litters as having puppies and raising them is a lot of work for her, and you too! Thanks for using Petco Pet Education Center, formerly Petcoach to help you care for Tasha.

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!