During the significant period of their lives, most women can have children. We start the monthly menstruation as adolescence strikes, but cycles stop at some point. The menopause marks the end of our years of possible childbirth. It is natural to be curious if dogs also have menopause.
So do dogs have menopause?
There are comparable aspects of human and dogs’ reproductive cycles. Both species have periodic hormone fluctuations, but the pacing, duration, and implications of those are quite different. Older, healthy female dogs—those who were not spayed— do not have menopause as human females, but their fertility decreases as canines age. While dogs bleed throughout their heat cycle, they don’t have monthly periods like women. The only sure sign of “menopause” is more rare estrus periods in a female dog.
How often are dogs in heat? Major stages of dogs hormonal cycles
We will concentrate mostly on estrogen and progesterone, even though many other hormones play significant roles in the reproductive cycles.
Something like this goes into the woman’s monthly hormonal cycle:
- Week 1: the period has just stopped, progesterone and estrogen levels are minimal
- Week 2: In preparation for ovulation, estrogen levels are increasing.
- Week 3: The levels of progesterone in anticipation of pregnancy are increasing.
- Week 4: In the absence of pregnancy, both estrogen and progesterone levels are decreased.
Dogs don’t get through a menstrual cycle every month. Instead, every four to 12 months, they go into “heat.”
Dog Heat Cycle
This is what the hormone fluctuations of a dog look like, suggesting a six-to-seven-month period:
- 1-4 months: low levels of estrogen and progesterone. No breeding activity.
- Week A (may last anything from several days to several weeks): preparing for ovulation, the levels of estrogen increase. The vulva of the dog is swollen, and bleeding is active.
- Week B: The estrogen level is decreasing (this period also may last from days to weeks). Ovulation has happened. The vulva continues to stay swollen, but the bleeding has decreased.
- Months 5 and 6: the level of estrogen is low. The levels of progesterone are high for pregnancy maintenance. The dog might experience a false pregnancy even if there was no mating. The reason – high levels of hormones are tricking the dog’s body into thinking that it in fact happened.
If a woman has menopause, her periods stop, and her body has deficient estrogen and progesterone levels for the rest of her life. This is not what happening in dogs. Healthy dogs will keep experiencing the ‘heat’ periods throughout their lives regularly. There are cases of dogs 16 years old who become pregnant. That is equivalent to a woman who is 80 or 90 years old!
At what age do dogs stop going into heat?
Never, usually. Dog’s estrus, also called heat, is divided into three phases and takes about two to three weeks. The first phase called Proestrus is the time a dog is bleeding. The second phase, called estrus, is when ovulation takes place, and the dog might become pregnant. The final stage, Diestrus, happens whether or not the dog is pregnant with regard to his hormones.
Most dogs undergo their first estrus cycle at the age of 6 months. However, it is sometimes later in larger dogs. For the next few years, except for when the dog was sprayed, she will undergo the cycle twice a year, although some breeds only experience it once per 12 months and some smaller breeds can have it three times a year.
As the dog grows older, her cycle becomes more erratic. If an older dog conceives, she is likely to give birth to much smaller offsprings than a younger animal, or not as many puppies as she had in her youth, described in her article Jennifer Coates, DVM.
Typically they start to be less able to keep their pregnancies healthy at the age of 5 or 6 years. But this may occur earlier than expected in larger breeds and later in smaller dogs, as their aging rates and life expectancies differ. Overall health status of a dog may also play a role.
A survey in beagles used for breeding showed that the deaths of newborn puppies had increased dramatically with the increasing age of the mother. At age 9, about 80% of the pups died before they weaned. For other breeds, the numbers may not be the same, but the trend is likely to be similar.
The occurrence of significant problems for the mother is higher with increased age, such as the problematic birth process or low levels of calcium and blood sugar. But even though fertility decreases, female dogs don’t stop having heats. So they don’t experience “menopause” as the human females do. The misconception comes from the fact that older dogs don’t always demonstrate the behavioral signs that they are in “heat”. Sometimes it is referenced to as a ‘ silent heat. ‘ It’s important to remember that even if your dog may not show signs of being in a “heat” during that age she still can become pregnant if mated.
Why stop a dog from going into heat?
The only way of stopping the dog’s estrogen cycles (without hormones) is to spay your pet or remove the ovary (a procedure known as oophorectomy). If your dog is fatigued, will not eat and drinks more than usual, it would be an appropriate time for consultation with your veterinarian for that.
Dogs are “built” to get pregnant during each heat. After each heat, they suffer from a “hormonal” pregnancy (two months of high progesterone and low estrogen) whether or not they are pregnant. That brings the risk for the development of a potentially deadly uterine infection named pyometra following each heat. Spaying a dog before its first heat provides virtually complete protection from mammalian cancer during its entire lifetime. Spaying a dog before its first heat provides sufficient protection from mammalian cancer throughout the rest of her lifetime.
Other advantages are the elimination of messy cycles, unwanted pregnancies, and the possibility of ovarian and uterine diseases (including cancer, benign tumors, cysts, infections, etc.). Spaying, of course, is not without possible future disadvantages, including an increased likelihood of constipation, some types of cancer and some orthopedic diseases.
Although all of the benefits and risks correlated with spaying can be difficult to evaluate, extensive research found that on average, spayed dogs lived much longer than those who didn’t. A vet who knows the condition of an individual dog can suggest whether or not she should be spayed (and when).
Menopause in dogs after spraying?
Most of the symptoms experienced by women during menopause are connected with decreasing levels of progesterone and estrogen. Since spaying leads to a similar scenario for dogs, the concern can arise as to whether they experience menopause. The truth is that we just don’t know. But based on their behavior after spraying It seems inconceivable that hot flashing, mood-swinging or any other symptoms usually associated with menopause would disturb them.
Credits: thanks for the cover photo to Robert Hell from Pixabay