Getting Into The Nitty Gritty Of A Dog’s Menstrual Cycle

Veterinary Tips, Pet Adoption Service

Menstruation is not an unknown concept to us. Assigned female individuals will prep for the potential pregnancy each month with the build up of their uterus lining, which will eventually break down once menstruation comes around. Apart from the bleeding, they’ll also have to deal with fluctuations of associated hormone levels as well!

Female dogs are lucky that they do not undergo this process as frequent as humans do. If you’re a first time owner of a female dog, here’s a brief rundown on how your precious furkid ‘menstruate’.

A Dog’s ‘Menstruation’ Cycles

Contrary to popular belief, not all mammals menstruate. In fact, only 16 types of mammalian species menstruate – it’s reported that there are 6,399 mammalian species in the world – and dogs are not one of them!

Dogs go through what is normally called the oestrous cycle, which is broken down into these four phases:

Anestrus: the state of inactivity, usually the longest out of the 4 phases.

Proestrus: the estrogen hormone will peak and the vulva will enlarge. This process usually lasts for 9 days.

Estrus: also commonly known as heat, this is when the female dogs are extremely receptive to males as they’re the most fertile time for breeding. This will last for an average of 2 weeks.

Diestrus: as estrogen level drops, progesterone peaks and the female dogs are no longer receptive to males. This process will last for 2 months.

The signs of heat aren’t apparent till dogs reach the proestrus phase, where their vulva will visibly appear larger and you may even begin to see bloody vaginal discharge. They may have increased appetite or a change in their personalities and adopt a few nervous tendencies. Your dog may also be urinating more frequently to signal to male dogs of their readiness via their pheromones and hormones that are present in her urine.

Your dog will be ready to breed when she reaches the estrus phase where her vulva will begin to shrink and the bloody discharge will appear to be slightly pinkish and watery. You may even start seeing flagging – an act whereby female dogs will begin to raise their tails high up or move her tail to the side – to show the male dogs that she is now allowing access to her vulva.

The progesterone hormone – the hormone responsible for maintaining pregnancy – will spike regardless of whether there is pregnancy or otherwise. This reasons why some dogs may show pregnancy symptoms such as weight gain, even when they’re not pregnant.

The last phase, anestrus, represents the end of the cycle. On average, a female dog goes into heat twice a year but there are special cases as well. Small breeds may go into estrus as often as every 4 months whilst larger dogs can remain in the anestrus phase for 2 years before they go into heat.

The Average Age Menstruation Starts

An average dog can go into their first estrus cycle when she reaches puberty. Similar to how humans can have different ages by which they experience puberty for the first time, the same can be said for dogs. Some may experience it when they’re merely 6 months old whilst others may reach their first cycle when they’re 2 years old.

What You Need To Expect

As a pet owner, you may need to do some preparations on your end. Your dogs may experience vaginal bleeding for at least a week or two; thus, you may want to purchase reusable diapers.

Since there is a fluctuation of hormones, don’t be all too surprised should your dog behave differently. However, do be warned that they may display anxious or even aggressive tendencies.

If you have the intention to breed your pets, you’ll need to ensure that accidental mating doesn’t occur. Since male dogs do not discriminate, there is a high chance that they might try to mate with his immediate relative. Inbreeding is highly discouraged as it can easily cause genetic problems should pregnancy occurs. If pregnancy still occurs despite your best efforts, you may want to head down to a veterinary clinic to get a shot containing dinoprost tromethamine that will help to slow down the progesterone production. On top of that, they’ll be able to give you veterinary tips on the next steps to safeguard your pet’s health.

To Spay Or Not To Spay

Pregnancies can be smooth or complicated, and if your dog is undergoing its first pregnancy, chances are it’ll be the latter. Some dogs are highly susceptible to birthing complications or dystocia and will need to have a Caesarean section surgery as opposed to natural birth.

If you’re not looking to breed your pets, it’s better to spay them when you can. Not only does it eliminate any potential accidental mating/pregnancy, but it also helps to prevent vaginal bleeding and semi-annual estrus. Furthermore, it significantly reduces the possibility of mammary cancer when she reaches a certain age.

If you’ve gotten your pet from SPCA or other centres with a pet adoption service, they’re most likely spayed and neutered but do double-check with those in-charge. If you’ve gotten your pet from a breeder, you’ll have to go to a vet for an extensive checkup, so you may want to sterilise your pet while you’re at it.