Visiting Veterinarian

Unwanted pet pregnancies

By Michele Gerhard Jasny V.M.D. - October 25, 2007

Not long ago a client stopped by with a problem. Seems her purebred female Labrador retriever may have inadvertently had a romantic interlude with a dog of a different breed... a Pomeranian in fact. What could she do?

"How did he reach?" was my initial response. Then I scratched my head and pondered her dilemma. I don't work with many breeders. I suspect my "think globally about all the unwanted puppies and kittens" spiel discourages them. But I'm happy to support clients who decide to breed their pets responsibly. This owner certainly fit that category. I wanted to help. In the old days, we used to give a "mismating shot" - an injection of estrogen called ECP. But it needs to be given within a few days of the encounter. It was too late for Lovey. My client had only learned about the event well after the fact. Besides, ECP has serious potential side effects and its use is now frowned upon.

"I'm in the middle of appointments," I said. "I have to refresh my memory about our options. Call me later."

Mismating is the term applied when a bitch is unintentionally bred and the owner does not want the litter that might result. Maybe Lovey is too young, or the male is not a desirable sire. Maybe the timing is wrong. Before you panic, determine the likelihood that Lovey is actually pregnant. If you witness the Lovey-Dovey event, have a physical exam done immediately. Dovey may have gone through the motions with no... ahem... results. Your veterinarian can use a swab and a microscope to look for spermatozoa. No sperm, no pregnancy. What if the presence of little swimmers confirms that Dovey did the deed? There is still less than 40 percent chance of conception with a single mating.

"Okay," you say. "Run a pregnancy test. Get Lovey to pee on a stick or something." Sorry. Canine physiology is different from humans. Hormone levels of a dog in early pregnancy and a non-pregnant dog are indistinguishable. There is no reliable way to pregnancy test for three weeks. Some veterinarians still give estrogen products like ECP in this period to induce abortion, but the risks include the possibility of irreversible sterility, serious uterine infection, and fatal aplastic anemi... and all this when odds are she didn't actually conceive anyway.

The absolutely best way to avoid an unwanted pregnancy at this point is to spay Lovey the moment she goes out of heat. Why wait even a day? Because during heat the blood supply to the reproductive tract increases and uterine tissue changes dramatically, becoming turgid and friable. Some veterinarians will spay a dog in heat. Not me. Too much bleeding. Too much risk of things tearing when you don't want them to. Nah. Sit back. Wait a week or two. It's easier and safer to spay a dog in early pregnancy than in full-blown heat. It is important, however, not to wait too long.

I once had a client bring a fat, fluffy cat to be spayed. In my presurgical exam, I discovered she was pregnant, but her owner felt strongly that she wanted us to proceed. In keeping with my "pet population control" attitude, I agreed. Once I got in, however, I saw that the kittens I was extracting were closer to term than I had thought. As I tied off the blood supply and lifted out the uterus in one piece, I could feel kittens squirming inside. I just couldn't do it. Making a quick cut through the uterine wall, I pulled the kittens out one by one, and passed them to my assistants to revive. A few made it. A few did not. I can't remember how the owner reacted to my unexpected delivery but I know that day I established a definitive policy that I will not spay an animal in the second half of pregnancy. It's too hard on the doctor.

Your options

Now what if it's still early enough to spay, but you really want to keep Lovey as a breeding animal? Obviously spaying will render her permanently sterile. What now? Well, we still have to confirm if she is pregnant. The best method is to wait until at least day 24 or 25 and then have an ultrasound, which by this time can differentiate false pregnancies from real ones, and give you an exact number of pups. No ultrasound available? By around day 30 you can do a blood test for Relaxin, the only pregnancy-specific hormone in bitches. You can get a false negative if you test too early and a false positive if she was pregnant but miscarried.

Once you know Lovey is definitely pregnant, it's decision time. You can have the litter and try to find them homes... or you can ask your veterinarian to medically induce abortion. Veterinarians may resist assisting with this for many reasons. Some may be uncomfortable with the concept, although most have done early surgical abortions via spaying without giving it a second thought. If we haven't done a medical abortion before, it's a headache to review all the procedures and get the necessary medication. There are potential complications and liability issues.

"Induce an abortion? Why not just have her spayed?" we ask. We have known too many people who repeatedly allowed mismatings to occur. But if you are a responsible breeder, like my client, who just got caught by unlucky circumstances, and you are sure you want a medically induced abortion for Lovey, there are a few reliable protocols.

The most commonly used abortifacient is prostaglandin, sometimes combined with other agents. Prostaglandins are not consistently effective for inducing abortions during the first few weeks but work well if you wait until after 30 days. It is a series of injections, two a day for at least five days, maybe longer. The injections are continued until ultrasound confirms that all fetuses have been expelled. That's hard to write, hard to read, hard to witness, but it is the reality. After each injection Lovey may show significant discomfort. The prostaglandins make smooth muscle contract, thus leading to uterine cramping, gastrointestinal distress, including nausea, drooling, vomiting, diarrhea, and panting. In other words, Lovey will feel simply awful for 30 to 60 minutes after each injection. But at the end of the protocol, she will no longer be pregnant.

Prostaglandins pose logistical challenges as they can be absorbed through the skin by the people administering it. Women of childbearing age and people with asthma or other respiratory disease must take extreme precautions when handling it. There are other drugs that may be used to induce abortion in the bitch such as RU 486, the "morning after" pill, but many are not currently available in the United States. Others may be extremely expensive, of unknown safety, difficult to dose properly, or pose concerns about human abuse and misuse.

Nothing is as safe, effective, painless, and cheap as prevention. But "Just Say No" doesn't always work. Dovey jumps the fence. The gate gets left open. The kids let Lovey out. Mismatings happen. That doesn't make you a bad owner. It doesn't even necessarily make Lovey pregnant. It does require that you and your veterinarian sit down and have a heart-to-heart and consider the options.