A female dog can experience the signs and symptoms of pregnancy without being pregnant. It's called a pseudopregnancy, also know as pseudocyesis, false pregnancy or phantom pregnancy, and is a normal part of your dog's ovarian cycle. The symptoms are usually mild and only last a few weeks, but sometimes, and for some dogs, they can be dramatic and debilitating. It's important to understand what's happening so you know how to help your pooch.
The Dog's Heat Cycle and Pseudopregnancy
An intact adult female dog comes into season twice a year, although a few breeds have an annual heat. The first phase of her heat cycle is proestrus, which lasts four to 15 days, and prepares her for mating. This is followed by estrus, lasting four to eight days, when she can fall pregnant. The third phase is called diestrus and lasts six to 10 weeks. This is the time when a non-pregnant dog has a false pregnancy. Her ovaries start producing the hormone progesterone -- the pregnancy hormone -- in the same way as when a dog has successfully mated. The increased levels of hormone cause changes in a female dog's behavior and body that mimic pregnancy. In a real pregnancy, this hormone stops just before the momma dog gives birth, but with a false pregnancy it gradually decreases after four to six weeks. As progesterone decreases it can stimulate mammary gland development and false labor in a non-pregnant dog.
Mothering Behavior and Physical Symptoms
During a false pregnancy, an adult female dog, at any age, may experience some or all of the behavioral and physical changes normally associated with pregnancy. After some heats, she may not have any symptoms. The intensity of the symptoms varies between dogs and from one heat cycle to the next for an individual dog. The classic symptoms of pseudopregnancy include nest building and adopting cuddly toys or other objects to mother and guard. Your pooch can also be restless, less interested in walks, go off her food, appear lethargic and she may be moody and whine a lot. Occasionally, a dog can become aggressive when she has a false pregnancy. Common physical symptoms include intermittent vomiting, fluid retention and a distended abdomen. Her mammary glands can become enlarged and they may or may not produce milk. In more extreme cases it's possible for your pooch to have a false labor with mild contractions.
Why Dogs Have Pseudopregnancies
It's not known for sure why dogs experience pseudopregnancy. In the past, all the females in a wild dog pack appear to have come into season at the same time, but only the dominant female dogs mated and had puppies. Some behaviorists think false pregnancies and milk production may have evolved so the lower-ranking females could nurse the pups while the dominant females were hunting, and to provide the pups with extra nutrition.
Symptomatic Treatments and Preventing Pseudopregnancy
In most cases, pseudopregnancy typically clears up within about three weeks without any medical intervention. If the symptoms persist or they cause your dog distress, your veterinarian may provide tranquilizers to ease her anxiety or diuretics to help with fluid retention and reducing milk production. Your dog may need to wear an Elizabethan collar if she licks her nipples, as touching the mammary tissue stimulates milk production. Hormonal treatments are only provided in rare cases. A veterinarian should be consulted if your dog is off her food for more than 24 hours or you notice a discharge from her nipples or vulva as there may be other problems. Also see a vet if there's any possibility your pooch is really pregnant. If your dog has a tough time during false pregnancies, spaying will prevent future episodes. It's important all signs of pseudopregnancy have finished before your dog is spayed or the false pregnancy could be prolonged.
- VCA Animal Hospitals: False Pregnancy or Pseudopregnancy in Dogs
- Veterinary Partner: Canine False Pregnancy and Female Reproduction
- Caring For Your Dog; Dr. Bruce Fogle
- Veterinary Notes For Dog Owners; Trevor Turner BVet Med, MRCVS