Understanding Your Female Dog's Heat Cycle

Photo: Meg Sanchez|Unsplash

Similar to menstrual cycles in humans, your furry one will begin to have a heat cycle once she is sexually mature. Female dogs periodically go in heat – a stage in the cycle known as oestrus.

When Will My Dog Get Into Heat?
Females dogs will get their first period when they reach puberty. This typically happens when they are six-months-old, but some have been known to get it as early as at four-months-old.

The exact age can vary according to the breed – smaller dogs seem to become sexually mature earlier.

How Do I Know That My Dog Is In Heat?
The most common “warning” sign is a swollen vulva, followed by some vaginal discharge.

When she’s no longer in heat, the discharge completely disappears and the vulva returns to its normal size.

How Often Will She Get Into Heat?
Most female dogs tend to go into heat at least twice a year, around every six months. That said, the interval may be several months longer or shorter too.

Some small dogs are capable of having a cycle at least three times a year, while some larger hounds only have it once a year. Their first heat cycle is usually irregular, and can take up to two years for before it goes on a regular basis.

How Long Does This Last For?
It usually lasts between two to three weeks.

Tips & Info:

Sometimes, the swelling of the vulva may not be obvious, and in some cases, the vaginal discharge will happen first.
The amount of discharge can vary from dog to dog, and even from cycle to cycle (of the same dog). It can range from small amounts of discharge to heavy bleeding.
For pooches with dark coats, this discharge may not be visible until you notice stains on your carpets and floors, so take extra note of your light-coloured furniture!
Throughout the cycle, the discharge usually changes in colour and appearance. It typically starts out bloody, and then becomes a watery, pink discharge as the cycle progresses.
A female pup in heat may also urinate more often, and develop a marking behaviour. As her urine (at this stage) contains hormones that inform male dogs of her fertility, marking is her body’s way of attracting potential mates.
This ‘potent’ pee can be pungent, and the smell can travel far! So do not leave your pup unattended outside when she is in heat, as male dogs can sniff her out and may try to mount her, leading to possible unwanted pregnancies.

*This article was updated on 20 Sept 2020. It first appeared in PetsMagazine.com.sg on 29 Jul 2016.