Question: Menopause and Dogs
This question comes
up fairly often, do dogs go through menopause? This, and a few other
concerns about canine reproductive health are answered here.
Answer: Unlike humans, dogs do
not go through menopause. Menopause is defined as the cessation (stopping) of monthly cycles.
Canine Reproductive Cycle Basics
Dogs do not have a monthly cycle, rather, they go into estrus
(also known as heat) roughly every six months. The regularity of their
reproductive cycle depends on the age, breed, and individual.
As a dog ages, the twice-annual estrus cycles may become irregular, but she is still fertile.
Pregnancy is still a possibility, but with greater risk in an older patient.
Potential Reproductive Problems in Unspayed Female Dogs
For dogs
that aren't spayed (uterus and ovaries removed = ovariohysterectomy,
ovaries only = oophorectomy), reproductive health risks increase. Here
are potential problems to be aware of in unspayed female dogs.
- Pregnancy - pregnancy in a middle=aged to senior
dog is considered a higher risk than a younger dog, due to age-related
conditions or diseases (known or subclinical) that may be present.
-
False pregnancy - This condition, also known as pseudopregnancy
or pseudocyesis. False pregnancy may occur at any age, regardless if
she was mated or not. During a pseudopregnancy, the corpus luteum
(temporary ovarian structure that secretes progesterone after an egg is
released, necessary to promote changes required to maintain a pregnancy)
does not regress as it should. With elevated levels of progesterone,
the body and brain respond as if pregnant, resulting in signs seen that
are common in late pregnancy: nesting behavior, territoriality,
mothering behavior (collecting toys, etc.) as well as mammary gland
development and milk production.
Most cases of mild pseudopregnancy resolve on their own in 2 - 3
weeks. Symptomatic treatment may be needed to reduce mammary discomfort
and behavioral problems (anxiety) associated with this condition. If the
dog will not be used for breeding purposes, spaying is recommended.
-
Pyometra - Pyometra is an accumulation of pus in
the uterine cavity. It is caused by elevations in the hormone
progesterone. As part of the normal estrus cycle or as part of a false
pregnancy condition, progesterone levels rise, causing the uterine
lining to be thick and "lush," ready for pregnancy. In the non-pregnant
uterus, bacteria enter and cause the uterus to become filled with pus.
The cervix may be open or closed, resulting in drainage from the
vulva or not. Pyometra may be lethal if not treated. Medical therapy may
be an option for some cases (never for closed pyometra), but the
preferred treatment is to spay. Spaying also prevents pyometra
development.
- Mammary Cancer - Similar to humans, mammary
(breast) cancer is common dogs who have not been spayed. Cancer may
occur in of of the 8 mammary glands, or as multiple cancers in the
mammary glands or associated lymph nodes.
In Summary
The only way to stop the estrus cycles in the dog
(without giving hormones) is to spay the dog (hysterectomy) or remove
the ovaries (oophorectomy)