Spaying Dogs in Heat and Pregnant Dogs

Yarmouth Veterinary Center

75 Willow Street
Yarmouth , ME 04096



Many veterinarians are very reluctant to spay dogs while they are in heat. The conventional wisdom is that 1) the dog’s blood does not clot as well when they are in heat and 2) there is an increased blood supply to the reproductive organs that we are removing during the spay procedure. 

(2) is true and (1) is not.  Due to the increased blood flow, spaying a dog that is in heat does carry some increased risk compared to spaying a dog that is not, but it is still a relatively safe procedure. At YVC, we are comfortable spaying a dog while it is in heat, but before we do so, we ask clients to consider several things:

- What is the risk of the dog becoming pregnant? This may be the most important question. We believe that if the risk of the dog becoming pregnant is high then it is better to spay the dog while it is in heat.

- Spotting blood, attracting male dogs, and occasionally a negative change in disposition are nuisances associated with being in heat. How significant are these nuisances?

-  A newly spayed-while-in-heat bitch will still potentially attract male dogs for several days. If a male dog successfully ties with this female, there could be disastrous consequences for the female due to trauma of the surgery site. 

-  If a dog is spayed within the first two months after being in heat, a very dramatic false pregnancy is somewhat likely to occur. 

-  Spaying a dog in heat typically requires up to 30 minutes of additional surgery time, and could require the use of the surgical laser, both of which will  increase the cost of the surgery. 

Taking all of these things into account, if you would like us to spay your dog while it is heat we are glad to do so. If you would prefer to wait, however, it is ideal to wait until your dog has been out of heat for three months. 

NOTE: We can also spay pregnant dogs. The particular concerns are somewhat similar to the concerns for spaying a dog in heat: There is an increased blood supply to the ovaries and uterus (the organs that we will be removing), and the uterus is larger than normal.

As with a dog in heat, these changes typically create the need for more surgery time and possibly the use of the surgical laser, thus increasing the cost of the spay procedure. 
Following the spay, the sudden hormonal drop stimulates milk letdown and possibly false pregnancy.

Yarmouth Veterinary Center