All About Dog Periods and Spaying | PetFirst Pet Insurance
Pet Care & Health

Not spaying your female dog? Here’s what you need to know about dog periods.

by PetFirst Pet Insurance
4 years ago


One of our PetFirst employees was looking at adding a new addition, a female miniature poodle, to his family and was weighing the option of not spaying her. We thought – I bet other pet owners are weighing the same decision! So, we decided to do the research for you, to help educate you on dog periods and what they can mean for you and your dog’s health.

The Female Cycle
A female dog will have her first estrus cycle, or what is commonly referred to as “in heat”, once they reach puberty. On average, puberty is reached around 6 months, but this will vary by breed. Larger breed dogs may not reach puberty until 18 months to two years of age, while smaller breed dogs may have their first period earlier than 6 months of age. This cycle can last around 18 days, or 2-3 weeks.

It can take up to two years for a female dog to regulate their cycles, but most dogs come into heat about twice a year. Some smaller breed animals will cycle more often- three times a year, while giant breed dogs will cycle much less, around every 12-18 months.

Signs of estrus:

  • Swelling or engorgement of the external vulva
  • Bloody vaginal discharge- Sometimes not apparent until several days after estrus has begun. The color and appearance will change as the cycle progresses.
  • More frequent urination
  • Exhibit “marking” behavior

Believe it or not, they do make dog diapers for females in heat. Or, if you are crafty, Pinterest offers a ton of DIY doggy diaper ideas and tutorials.

The Controversy of Spaying Your Dog
This topic causes a lot of emotion and passion for many pet owners and veterinarians. As with many important decisions regarding health, there are both positives and negatives. Laura J. Sanborn, M.S. reviewed an extensive amount of veterinary medical literature and summarized the findings. Here is the list of pros and cons for spaying females she notes in her dissertation.


  • Greatly reduces risk of mammary tumors if done before 2.5 years of age (mammary tumors are the most common malignant tumors in female dogs)
  • Nearly eliminates the risk of pyometra (a uterine infection that occurs as a result of hormonal changes in the reproductive tract)- which affects about 23% of intact female dogs
  • Reduces the risk of perianal fistulas
  • Reduces the risk of uterine, cervical and ovarian tumors


  • Increases the risk of bone cancer (osteosarcoma) if performed before one year of age
  • Increases the risk of liver and spleen cancer (splenic hemangiosarcoma) and heart cancer (cardiac hemangiosarcoma)
  • Triples the risk of hypothyroidism
  • Increases the risk of obesity
  • Can cause urinary incontinence
  • Increases the risk of recurring urinary tract infections
  • Increases the risk of recessed vulva, vaginal dermatitis and vaginitis, especially if performed prior to puberty
  • Doubles the risk of urinary tract tumors
  • Increases the risk of orthopedic disorders
  • Increases the risk of adverse reactions to vaccinations

For female dogs, the number of health benefits from spaying may outweigh the potential long-term problems. Unfortunately, weighing these risks and benefits will vary from dog to dog. Breed and age are variables that must be considered when decided whether or not to keep your female dog intact.

Nothing in this article should be construed as financial, legal or veterinary advice. Please consult your own advisors for questions relating to your and your pet’s specific circumstances.

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