Spaying cats is good for them but low estrogen in humans is bad for us

All the reports state that spaying female cats is a good thing for cats and humans. They say the operation does not change her basic personality. It makes her less irritable at certain times of the year. There’s less chance of heat-related marking and spaying does not make your female cat lazy and fat. The cats are healthier. Spaying appears to slow the metabolism of female cats but, as mentioned, it’s nearly always positive which begs the question as to why the effects of low oestrogen in humans is negative.

Feral or Stray Cat Being Spayed
Feral or Stray Cat Being Spayed. Photo: by Rocky Mountain Feline Rescue
Until September 7th I will give 10 cents to an animal charity for every comment. It is a way to help animal welfare without much effort at no cost. Comments help this website too, which is about animal welfare.

Low Estrogen in humans

Spaying of female cats includes the removal of the uterus and ovaries. The ovaries produce oestrogen. There are many symptoms of low oestrogen in humans, one of which is depression. Estrogen is thought to increase serotonin which is a brain chemical that boosts mood. A deficiency of oestrogen, as is the case when the ovaries are removed under the spraying operation, may cause a decline in serotonin causing depression.

I’ve made the supposition that cats have similar brain chemistry to humans in that they have serotonin. I don’t know if it’s true but physiologically cat and humans are similar. Ironically, cats increase the human’s production of serotonin.

Does spaying cause cats to become depressed?

Do we know if female cats become depressed after being spayed? Not a lot has been written about it but what has been written has probably been ignored because spaying female cats is considered obligatory. It is certainly routine in order to stabilise the domestic cat and feral cat population.

On the website there is reference to what appears to have been a study by Cheryl Frye, who believes that the spaying of cats results in a modest but consistent increase in anxiety and depression.

There’s nothing in the veterinary books that I have indicating depression in female cats after the spraying operation. I don’t consider this conclusive because veterinarians give little thought to the possibility that a female cat will be depressed after the operation. As I said it has to be done and therefore the consequences are accepted. In any case you can’t get into the mind of the domestic cat with certainty.

I just think there appears to be a convenient lack of interest in how the removal of the production of oestrogen in a female cat through the removal of her ovaries affects the cat emotionally. I’m not suggesting anything should change. And I’m not suggesting that people should stop spraying their female cats. It is necessary and I wholly support the operation but I think we need to consider the potential side-effects a little more than is currently the case.

Does spaying cause bone loss in cats?

Other effects of low oestrogen in humans include weak bones because estrogen helps to keep the bones healthy and strong. A reduction in oestrogen may cause bone loss. Postmenopausal women have an increased risk of developing osteoporosis and suffering from bone fractures.

Way back in 2010 Christie Keith, writing on remarked that it was difficult to find information about the medical risks of spaying and neutering pets. There is nothing that I can find on bone loss because of the spraying operation.

If there was loss of bone in female cats after being spayed you wouldn’t know about it anyway. No one is checking and most domestic cats are not physically exerted to the point where deficiencies in bone mass become evident.


My conclusion is that in order to be completely fair to domestic cats it would be sensible to carry out a study on spayed female cats looking for the side-effects as mentioned. However, I don’t expect it to happen because it would be politically incorrect as it would potentially undermine cat owners’ motivation to spay their female cats. This would be disastrous in the grand scheme of things.

Even today, after much pressure on people to spay their female cats there is still a small section of society who don’t do it or don’t do it soon enough which is a contributing factor in the overpopulation of domestic cats or, to put it another way, the continued presence of unwanted cats at shelters.


1 thought on “Spaying cats is good for them but low estrogen in humans is bad for us”

  1. I believe that my female cat has become more anxious and less tolerant to many things since her spay and considering that estrogen is important for us humans, why not animals. Perhaps pets should go on hormone replacement therapy similar to menopausal woman. Obviously pets need to be sterilized, but my cat has had a tough life and it certainly does not make me too happy either


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