Can You Spay a Dog or Cat in Heat (Estrus)?

Spaying a pet while she is in heat is more costly than when she isn't

Lumina / Stocksy United

You meant to have your dog or cat spayed before she came in heat, but you didn't expect it to come so soon. Dogs and cats have their first heat between 4 to 6 months of age. Although, you can ask your vet spay a dog or cat in heat (also known as estrus), many vets prefer to wait until the heat cycle is over. The size, age and overall health of the pet are considered as well. If the spay is done while the animal is in heat, the costs are usually a little higher.

Spaying While In Heat

During a heat cycle, the blood vessels that supply the ovaries and uterus are engorged. Additionally, these tissues are more "friable"—may tear more easily than normal—and bleed more. Even tissue not associated with the reproductive organs such as skin, fat and muscle often seep more than normal during surgery.

This makes a typically elective surgery more stressful than it needs to be and carries the additional risk of bleeding problems during the surgery or post-operatively. Some veterinarians will not spay a pet in heat and recommend that surgery be scheduled a week or two after the cycle ends.

Some veterinarians are selective about the type of pet they will spay while it is in heat. In general, cats that are in heat are easier to spay than dogs that are in heat. Small dogs are easier than large dogs. Overweight pets are difficult to spay both in heat and not in heat.

Anesthesia is riskier for overweight animals too—just one more reason to make sure your pet is not overweight.

Additional Costs When Spaying a Pet in Heat

If a pet is spayed while in heat, the surgery takes longer and additional surgical supplies such as gauze sponges and sutures may be needed. IV fluids during surgery are standard for many practices and are built into the surgery cost.

For some practices, this may be an additional cost for an in-heat spay. 

Planning Ahead

Dogs and cats are typically spayed by 4 to 6 months of age. If the animal is spayed before the first estrus cycle, the chances of mammary cancer are greatly reduced. Spaying at any age eliminates the chance of ovarian and uterine cancers, as they are removed during a typical spay. Some animals, especially those at shelters, are spayed and neutered at much younger ages.

The "best" age to spay and neuter is a topic of much debate. Speak to your veterinarian about your specific pet for advice on the best age to spay. Most people agree that it is best to avoid spaying when in heat if possible.

Sometimes an appointment is made in advance or an animal is found or rescued and the estrus status is not known when the surgery is scheduled. If this is the case, speak to your veterinarian about possible risks and added costs of spaying the animal while it is in heat.