Visiting Vet: The jury is still out

When is the best time to spay or neuter?


One of my favorite families lost two dearly loved dogs in recent years, so I was delighted when they arrived at my door, pre-pandemic, with Joy, their new 5-month-old golden retriever. In the past, I would have recommended scheduling Joy promptly for her ovariohysterectomy, commonly known as a spay. This surgery consists of removing both ovaries and uterus so a female dog can no longer go into heat or get pregnant. Spaying young dogs relieves owners of having to deal with the vagaries of the canine estrus cycle. It also protects dogs against mammary cancer later in life, and eliminates the risk of a life-threatening uterine infection known as pyometra. Despite these benefits, recommendations about when, and even if, to perform this surgery are not consistent. In much of Europe it is common not to spay female dogs at all — but many of those countries have a better handle on controlling the pet population than we do here in the United States. Here, pet welfare organizations promote early neutering of dogs and cats to curb the overpopulation that results in millions of unwanted pets being euthanized every year.

“So when should we get Joy spayed?” my friends asked. Thirty-five years ago I would have said with confidence, “When she is 6 months to a year old.” That was the conventional wisdom back then — let her mature a bit, but avoid having her go into heat, thus eliminating the risk of mammary cancer and unplanned pregnancy.

Fifteen years ago, however, my answer would have been different. At this point in time, many shelters had instituted “early spay/neuter” programs, doing surgery on pets as young as eight weeks old to insure that all animals adopted out could be guaranteed not to reproduce. I personally preferred to wait until an animal  was a minimum of 4 months old. At that age the immune system is mature but reproductive organs are still fairly small and not too vascular. In addition, pups this age are rarely overweight. Spaying a 4-month-old pup is a much easier procedure than the same surgery on a bigger, older, fatter bitch. Much, much easier.

Ask your average veterinarian what is their least favorite surgery and many will say “big old fat dog spays.” Why? Well, without too much gory detail, there is a moment when the surgeon needs to feel for the ovarian ligament deep within the abdomen, then blindly snap it loose . . .  without tearing the adjacent ovarian artery. (Squeamish readers, skip this paragraph.) Tear the artery and you’re playing hide-and-seek in a belly full of blood trying to find and clamp that bleeder. There are other challenges, too. Don’t leave behind even a tiny bit of ovary or the dog may still cycle. Don’t inadvertently tie off the ureter, which connects kidney to bladder. Don’t nick anything you shouldn’t, like spleen, liver, or bladder. Although owners think a spay is “routine” and never expect complications, it can actually be fairly difficult surgery. Doing it when a pup is younger, smaller, thinner, and less developed is less stressful for the surgeon, and young dogs seem to bounce back faster post-operatively. Nowadays some veterinarians may also offer options such as an “ovary-sparing spay” in which only the uterus is removed. You can even have your dog’s procedure done laparoscopically at some major veterinary facilities. But most owners still have the traditional surgery in the traditional way.

So why did I pause when my friends asked when to get Joy spayed? Because recent studies have suggested some downsides to neutering dogs prior to full maturity. The topic is a source of controversy in the veterinary community. Do the advantages of pre-pubescent spay outweigh the newly suggested negative side effects? The jury is still out, but after much discussion Joy’s owners decided to delay spaying until she was 12 to 18 months old.

Fast forward a year. Joy is now 17 months old, and we’re in the middle of a pandemic. She has been through a heat cycle, maybe two. Her owners, being excellent dog parents, have managed well, keeping close tabs on her. It has come time for her annual visit to the vet. Joy’s dad drops her off following our “no contact curbside protocol.” Meanwhile, Joy’s mother has emailed me a list of questions and concerns including a request that I check Joy’s tummy as she seemed a bit bloated and her nipples are enlarged.

Sure enough, Joy’s belly looked a bit big. So did her nipples. I gave one teat a gentle squeeze. Uh oh. Milk. Was Joy in the family way? I called her dad who was waiting patiently outside in his truck. “When did she last go into heat?” I asked. He wasn’t sure. I understand. That’s more of a mom thing. “Do you ever leave her outside unattended?” I asked. Only in the fenced yard. “I’m afraid she might be pregnant,” I continued. “Is the fence low enough that a determined male dog could jump it?” Dad couldn’t be 100 percent sure, but would be shocked if that had happened.

Twenty anxious minutes and one radiograph later I was able to backtrack and change my diagnosis. With no puppies visible on the  X-ray, I realized Joy was experiencing pseudocyesis — a false pregnancy. The underlying hormonal events causing pseudocyesis is poorly understood and presentation varies dog to dog. Physical signs may include abdominal distension, mammary gland development with or without milk production, vomiting, poor appetite, and even rarely the appearance of going into labor. Behavioral changes can include nesting, restlessness, and “mothering” inanimate objects like stuffed animals. Although drugs can be used to stop pseudocyesis, it is actually a “normal” occurrence and usually resolves spontaneously in a few weeks. It does not affect future fertility, but Joy’s owners had never wanted to breed her anyway. They simply had the same question as a year ago. “So when should we get her spayed?” This time the answer was easy. As soon as possible after those false pregnancy symptoms resolve.