We have been asked, do dogs get periods? The answer is yes, they do (sort of…). But the way their menstruation cycle works isn’t the same as cats or humans, so let’s explain a bit more. 

Table of contents

Sexual Maturity

Most dogs become sexually mature by around 6 months, although this can vary between breeds. At this point they are still in the puppy stage of development both physically and emotionally, but their sexual organs are fully developed, making them capable of reproducing. Sexual maturity does not necessarily correlate with physical maturity, which is why we can often have problems when female dogs are mated (hopefully unintentionally) before they are emotionally and physically ready. Physical maturity depends on the breed and size of dog but can happen any time from around a year to even two years in our large or giant breeds.

How often do they have their cycle?

Whereas a human’s cycle is around 28 days, dogs typically come into season, sometimes known as ‘heat’, around twice a year or around every 6-7 months. There are certainly some variations in this, and some breeds like the basenji are known to have less frequent intervals due to an incredibly interesting phenomenon called the ‘photoperiod’. Domestic animals have shown a trend in not needing the photoperiod to regulate the reproduction cycle and for breeding anytime during the year, but the Basenji is an exception.

There is a fantastic article that details all the phases well here.

The Oestrous Cycle

A female dog’s reproductive cycle is called an Oestrous cycle and is broken down into four different phases:

The four phases are:

  • Pro-oestrus (follicular phase)
  • Oestrus (heat) 
  • Metoestrus (luteal phase)
  • Dioestrus

Let’s look in more detail…

Pro-oestrus (follicular phase)

Pro-oestrus is the beginning of the heat cycle, otherwise known as the follicular phase – the Graafian (mature) follicles develop in the ovary and secrete oestrogens. This is the phase that you may consider a ‘period’ as it is characterised by the bleeding from the vulva.

Pro-oestrus is characterised by swelling of the vulva and a blood-tinged vaginal discharge. Female dogs will not normally allow mating to occur in this phase; it can last anywhere from a few days to four weeks.

Oestrus (heat) 

Oestrus is also known as “heat.” This is when ovulation normally occurs, the female is ready to mate and becomes sexually attractive to the male. This is the time when the female dog will allow mating to occur or ‘stand’. This phase of the cycle lasts anywhere from three to 21 days(!) although usually about a week.

Metoestrus (luteal phase)

Metoestrus lasts for approximately 55 days. In this phase the corpus luteum, a temporary endocrine structure in female ovaries, develops from ruptured follicle. During this stage, the corpus luteum continues to produce progesterone, which will maintain the pregnancy if the bitch has been mated and is pregnant. In a non-pregnant bitch, the progesterone secretions continue for approximately the same amount of time and then progress to the next stage of the cycle, because of this it is during the metoestrus phase that pseudopregnancy occurs in a non-pregnant bitch.

Anoestrus

Anoestrus is defined as the timeframe when cycling ceases. In dogs this is typically 4 months, during this time there are no external signs. In a non-pregnant bitch, levels of progesterone slowly decrease, whereas progesterone levels reduce suddenly at parturition (birth) in pregnant bitches.

Further reading: