The Canine Heat Cycle: A Complete Guide

The canine heat cycle refers to the period when the female or bitch is in season i.e. a period when she is ready to mate or breed. The cycle is more technically known as the estrus.

The heat cycle normally occurs from the age of 6 – 12 months although larger breeds dogs can be in season at an older age, sometimes when they are 12 – 24 months old. The heat cycle will normally last for about 3 weeks or 21 days.

Although this lasts about 3 weeks they are only capable of breeding or getting pregnant for about 3 – 21 days in the entire 3 week period. An interesting fact is that dogs will carry on having periods for their entire lives, which is of course different for humans who stop having periods at a certain age.

Symptoms of Pregnancy in Dogs…

Your beloved little dog is now an adult and will start to lick and pay more attention to her vulvar. Your dog’s vagina may also be swollen.

It is very common for your dog to bleed from her vagina, the flow of bleeding maybe heavy or slow, but the amount of bleeding will decrease as the month goes on. At the beginning of the cycle the blood will often be a dark red color but as the season progresses it will become more of a salmon color.

Although the vagina will appear swollen at the beginning it will begin to become softer later in the month, this is due to the progesterone levels rising which prepares her ovaries for the release of her eggs. You may see your dog start to curl her up tail on either the right or left side and she may even urinate more often as she wants to spread her scent to the males.

Stages During the Canine Heat Cycle

Stage 1 – The first stage is known as the proestrus stage where your dog will urinate more, have swelling around the vulvur. This is the period where the male will want to mate. This stage will last about 9 days and is when the pituitary gland starts to produce the hormones that help to encourage reproduction. The two main hormones that help to achieve this are the Follicle Stimulating Hormone (FSH) and the Luteinizing Hormone (LH).

The FSH is very important as it helps to increase the size of the follicles which enable the ovum to develop. This is what causes the vulva to start to swell (leading to the bloody discharge). You need to keep a close eye on your dog as during this stage some dogs are very keen on cleaning the area around the vulva (so the bloody discharge maybe cleaned up before you notice).

Stage 2 – The second stage is known as the estrus. This is the stage where your dog will allow a male to mate with her, this can happen from anywhere from 3 – 21 days.

Stage 3 – The third stage of the cycle is known as diestrus where she is beginning to come out of season. At this point she will not be so keen to mate. This stage can also last for different amounts of time varying from 4 – 14 days.

The next canine heat cycle will start from about seven months from the last time she was in season.

False Pregnancy – The cause of a false pregnancy is due to a misunderstanding in the hormonal changes. An increase in prolactin and decreases in progesterone are a common cause of false pregnancies.

A dog that is suffering from a false pregnancy may show some of the following symptoms…

  • She may start to nest.
  • Your dog may also start to mother objects around the House.
  • She may start lactating. Believe it or not she may even look like she is going into labour.
  • Your dog may also suffer from abdominal distension.

Canine Pregnancy Calender: If you want to be accurate when using a pregnancy calendar for you pooch, you need to know when your dog mated.

  1. After about 24 – 48 hours the eggs will be fertilized in the oviducts.
  2. After about 10 – 11 days the eggs will become what is known as blastocytes. The blastocytes will then develop into embryos.
  3. After 15 days your dogs nipples will start to become pink and enlarged.
  4. After 20 days your dog’s fur on the stomach will become thinner.
  5. From days 21 to 28 your dog may develop morning sickness just like in humans.
  6. After 1 month in the pregnancy calendar it is important that you feed your dog appropriately. A smaller meal is much better than a big meal. You may notice that your dog spends more time grooming and her nipples may appear sore.
  7. Six weeks into the pregnancy calendar your dog may completely lose her appetite and her abdomen will be really large.
  8. Two months into the pregnancy calender your dog’s nipples will ooze milk when squeezed. Your dog’s rectal temperature will also drop from approximately 101 degrees to about 98 degrees.
  9. After about 12 hours from this point the little puppies will be delivered.

Detecting a Pregnancy.

There are actually no infallible methods to confirm a pregnancy in your dog during the first three weeks (21 days). Some of the changes that you may notice can include the following.

1. It is very common to see behavioral changes in your dog during the early stages of the pregnancy. A dog in the early pregnancy may appear withdrawn  from her owners or from her normal routine.

2. Your dog may also show some physical changes – this maybe in the way she carries herself when she walks, she maybe depressed and she may have an increased desire for food.

3. It is not unusual for some pregnant females to exhibit Coprophagia (this is when a dog eats their poop). In some rare cases a pregnant dog may even eat other dog’s poop. “This is often caused by unclean living conditions, a dietary insufficiency, a mineral or vitamin deficiency or a combination of all of these factors”. (Harris, 1993).

With thanks to Geoffrey Llewellyn’s Book ‘Homeopathic Remedies for Dogs’ we have listed a collection of great remedies for variety of pregnancy related problems.

Below are some great remedies for problems associated with Whelping:

1. Arnica Montana 30c – give one tablet twice weekly during the week before birth and then one tablet twice a day during the birth. This is a great treatment for helping to reduce any damage (bruising) to the birth canal. It is also a great treatment for reducing the bruising and damage caused by a Caesarean (this is due to the healing properties of the Arnica).

2. Caulophylllum 30c – give this once a fortnight during the pregnancy.

3. Causticum 30c – this is a great homeopathic remedy for uterine inertia – this is when the uterus becomes tired and contractions cease. Give this remedy once every half hour until the contractions start again,


Llewellyn, G. 1998. Homeopathic Remedies for Dogs.

Mash, H. 2011. The Holistic Dog: A complete guide to natural health care. The Crowood Press.

The American Animal Hospital Association Encyclopedia of Dog Health and Care, 1994. Quill. New York.

The Doctors Book of Home Remedies for Dogs and Cats. 1996. Rodale Press Inc, Emmaus, Pennsylvania.