Post Spaying Problems

Question
I had two of my Siamese cats (mother and daughter) spayed about 5 weeks ago.  The daughter, Isabel, was a single birth from Sadie's only litter.  Sadie was a very high-strung mother and wouldn't leave her kitten alone at all.  For two years she would follow a pattern of coercing Izzy into feeding.  This followed a pattern almost with her heat cycles.  It seemed as though she was trying to remain ready for new kittens.  She was not being bred during this time.  After she was spayed, she started to gain weight rapidly and started to look pregnant with her breasts growing almost instantly.  She was 9 pounds before the surgery and is now at 14 pounds, only 6 weeks later.  I called the vet that did the surgery when I was worried two weeks later and she said "Is she eating?", and then "Then she's fine."  Sadie seems so huge to us now and I feel bad for her.  She is obviously uncomfortable when she tries to position her overgrown body.  She always jumped up high on a particular shelf where she slept.  She tried recently and fell a little over half way up because she is just too heavy to do it.  She is not used to her new size.  I am worried about her, but yes she does eat ok.  She isn't sickly but does sleep more.  Should she go to a better vet or are we really overreacting?  Thank you for your input.

Answer
Hi, Wendy.  Sadie should definitely see a vet.  While some weight gain is normal after spaying, weight gain this rapid and drastic is absolutely NOT okay.  The cause of the weight gain may be serious within itself.  Regardless of the cause, obesity is as dangerous in cats as it is in people.  It very often leads to respiratory problems, heart problems, arthritis, and diabetes.

There are a million and one things that can cause sudden weight gain.  Anxiety disorders, which cause the cat to overeat, are one.  Hypothyroidism, which also causes the lethargy and weakness you're seeing, is another.  

Pseudopregnancy (false pregnancy) could be to blame.  This can happen in cats, spayed or not.  While it's somewhat uncommon, it CAN actually be caused by a spay.  Spaying results in a sudden drop of progesterone (a hormone produced by the ovaries), which subsequenntly results in a spike in prolactin, the hormone that causes lactation.  This can confuse the body and cause it to feel pregnant when it is not.  Many cats will gain weight and actually look pregnant - big, round abdomen, swollen mammary glands, and all.  Pseudopregnancies are not harmful and have to be waited out.  Around the time that the cat would deliver if she was truly pregnant, the pseudopregnancy ends, and the cat's weight returns to normal.  As hormone levels even out after the spay, pseudopregnancies are less likely.

Many types of hormonal imbalances can cause weight gain, and since a spay removes the ovaries, which are responsible for producing various hormones themselves, spaying can upset the balance.  These normally even out within a few months after the spay.

Weight gain can also be a SYMPTOM (as opposed to a cause) of diabetes in its early stages, due to increased appetite.

I've only touched on a couple possibilities, here.  Hopefully, Sadie's weight gain is simply a overreaction to the spay that will correct itself with time.  However, you can't ignore this huge amount of weight gain because of the potential health risks.  So I do recommend to find another vet who feels the problem is worth looking into.

Best wishes,
Jessica