Unspayed Female Pets With Diabetes

By Dr . Joi Sutton|2023-09-27T14:43:47-04:00Updated: December 5th, 2013|Pet Care, Pet Diabetes, Pet Newsletter|13 Comments

The other day I met a client with a several year old intact (non-spayed) female dog. I suggested to her that we perform an ovariohysterectomy. Her response was that she has had pets her whole life and had never spayed any of them.

There are good reasons for spaying a female dog or cat such as dramatically lowering the risk of mammary tumors, curbing the pet overpopulation situation, avoiding the mess when they come into season, and removing the chance of uterine infections. Most pets are spayed in their youth, long before they might become diabetic later in life. Nonetheless, intact female pets with diabetes should definitely be spayed.

For our pet owners with diabetic pets it really is critical to spay the pet as soon as possible. The reason for this is that as a pet cycles, the hormones can affect glucose regulation. Progesterone has been called the hormone of pregnancy. Progesterone is a potent antagonist of insulin. You may have heard of humans with gestational diabetes when pregnant. It can happen to pets, too. Progesterone levels also rise when a pet comes into heat. Dogs usually come into heat twice yearly, and each of these cycles lasts typically 3 to 6 weeks. Cats are induced ovulators. Cats may come into heat repeatedly unless they are bred. Cats tend to be more vocal (obnoxious?) about being in season than dogs, but unlike dogs they don’t typically have a discharge while in season.

Imagine thinking you have finally sorted your pet’s insulin dose requirement and then come the hormones of a heat cycle. Suddenly your pet may start drinking and peeing more. You wonder if the insulin went bad. You blame your vet for being a dummy. You grumble about going in to pay another exam fee or roll your eyes when your vets says, “Run a glucose curve at home”. Really, if a pet isn’t spayed, you should anticipate periods when your pet is NOT regulated until you proceed with the spay.

Now, what to do with the anesthesia on the day of the surgery? We recently discussed anesthesia for the diabetic pet. Always speak with your vet regarding his or her favorite approach to handing anesthesia for a diabetic pet! You can anticipate your vet checking the blood glucose several times that day and giving a lower morning dose of insulin since your pet will be held off food before anesthesia.

As always, I enjoy interaction with our readers. If you have any questions, feel free to contact me at [email protected].

NOTE: Consult your veterinarian first to make sure my recommendations fit your pets special health needs.

About the Author: Dr . Joi Sutton

Dr. Joi Sutton is a 1993 graduate from Oregon State University. She has practiced both in emergency medicine and general practice. Dr. Sutton has done extensive international volunteer work though Veterinary Ventures, a nonprofit organization that takes teams of veterinarians to undeveloped countries for humane medical care. She also runs a small animal practice in South Florida. Connect with Dr. Joi on LinkedIn


  1. Athey G Bass July 15, 2023 at 9:49 am - Reply

    12yr dashound diagnosed about 6 months ago and we were trying to get her regulated so we could have her spayed. But she has gone into heat and her BS is running in the 400s. Vet said not to increase insulin. How long can she run this sugar. She seems ok right now. But should we go ahead and spay her. Or wait this heat out and make hen do it

  2. Heather March 21, 2021 at 8:29 pm - Reply

    Hi I’m a nervous wreck to get my 12 year old 3 legged diabetic cat spayed..its on March 31st I’m just so scared of complications due to her diabetes….

    • Dr . Joi Sutton March 27, 2021 at 7:23 am - Reply

      Worrying doesn’t help. Chat with your vet about the game me plan for the day of surgery. Make sure your sweetie has an IV catheter and fluids during the procedure. The IV catheter provides ready access to administer dextrose should the blood glucose drop. When I anesthetize a diabetic pet I always check a blood glucose immediately pre-op then every 20 minutes or so during the procedure with my Alphatrak blood glucose meter. A cat spay shouldn’t take longer than about 15 or 30 minutes if done by an experienced veterinarian. Don’t go to a low cost spay neuter clinic for a diabetic pet spay. Make sure they use gas anesthesia and incubate her and have her on fluids and run pre-op labwork. Make sure that they have all the anesthetic monitoring equipment for her. I like to say that we type A personalities can be irritating to have in your family, but we are the ones you want anesthetizing your pet. Do chat with your vet about your concerns so that he or she can put your mind at ease and you have common expectations.

  3. Fiona OSullivan February 19, 2021 at 11:49 am - Reply

    I have a Weimaraner collie cross who had a false pregnancy and diabetes. She was spayed in December but is still on insulin for the diabetes. If it is gestational, how long after being spayed can it take for the diabetes to go? (How long before we know if it is for life or not)

    • Dr . Joi Sutton February 21, 2021 at 12:46 pm - Reply

      I wish I had an exact answer for you. Keep checking her blood glucose, and les hope that the insulin resistance from the progesterone fades and she goes into remission. It’s still possible.

  4. Sanja Markovic January 8, 2021 at 5:54 pm - Reply

    Hello, we just had my 12 year old Maltese spayed as she was diagnosed with diabetes 2 weeks ago and developed insulin resistance. Two days after surgery, her glucose levels are still high (21) so I was wondering low long it normally takes for sugar levels to start going down after spaying?

    • Dr . Joi Sutton January 10, 2021 at 4:36 pm - Reply

      Diabetes can be from multiple causes. She may yet be diabetic once her progesterone fades away over the coming weeks after her spay surgery. Progesterone can cause insulin resistance. I hope her diabetes was only from the hormones, but time will tell. Do home test and keep in touch with your veterinarian so you have a game plan.

  5. Di August 29, 2020 at 8:11 am - Reply

    My diabetic dog also has leukaemia and my vet does not want her to undergo surgery. This is her first season since being diagnosed with diabetes and I hope we can keep everything under control.

    • Dr . Joi Sutton August 29, 2020 at 9:29 pm - Reply

      Progesterone is the hormone of pregnancy and causes insulin resistance. (That’s why
      Regent women can get gestational diabetes.) Clearly your vet has examined her and I have not… I don’t feel I can give you an opinion regarding it it is safe to have surgery since I’ve not examined your pet nor know any meds she might be taking. I hope her estrus goes by quickly and uneventfully!! You should probably step upper glucose testing while she is in heat and have a plan with your vet regarding insulin dosing based on her glucose levels.

  6. BW August 6, 2020 at 5:18 pm - Reply

    How long after a heat cycle will sugar regulate? We just got my female regulated enough for spay and she came in heat 🙁

    • Dr . Joi Sutton August 11, 2020 at 10:05 pm - Reply

      Well, it is extremely hard to regulate an intact female. I would likely proceed with the spay at this t8me if all else is fine. The reproductive tissue may be a bit more fragile or friable during a spay (why vets prefer the pet isn’t in heat for a spay), but a spay in heat can certainly be done. And of course your vet will likely keep a close eye on the blood glucose before, during and after the surgery. A heat cycle can last 1 to 6 weeks.

  7. Anne-Marie Le Roux November 9, 2019 at 2:23 am - Reply

    This article has helped me tremendously to understand why my pet has complicated diabetes and after reading this, I’ve immediately booked a spay for her. My vet has been suggesting that she gets spayed but I was worried about complications. But now that I understand better, the decision is made. Thank you so much for this!

    • Dr . Joi Sutton November 9, 2019 at 3:29 pm - Reply

      Great! I like to say that education is key to a well regulated diabetic pet. 🙂

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