The Truth About False Pregnancies

As Lorna Boydston's Great Dane approached her due date, she gave every indication that a big litter was on the way. She was huge, and as Boydston described her, "a walking dairy bar." Labor began, but after hours of straining no puppies were produced. A certified vet tech, Boydston, of Colbert, Wash., couldn't feel any puppies, so she took the bitch for a radiographwhich showed why. There weren't any puppies. Yet the labor continued for another 36 hours.

Coffee, a Labrador Retriever mix and the childhood dog of Glenda Parks, of Baton Rouge, La., had a huge litter. She was a doting mother, gathering them up to nurse whenever they strayed. She had one favorite, though, that she would lay with for hours, encouraging it to nurse; everyone in the household, dog and human alike, knew better than to touch the special baby. The puppies bore little resemblance to their dam, however; like the special puppy, which was in fact a plastic toy hamburger, they were all dog and child toys.

Idibidi, a Doberman Pinscher owned by Kim Floyd, of Riverview, Fla., bypassed the need for puppies by licking and suckling her mammary glands. This, in turn, encouraged milk production, and she became her own snack bar. Unfortunately, Idibidi eventually developed mastitis, and then mammary tumors, necessitating spaying and breast surgery.

Like 87 percent of intact bitches do at least a couple of times in their lives, these bitches were experiencing what's called a false or pseudopregnancy. All non-pregnant bitches have increased mammary development between six and 20 weeks following estrus, with maximum size occurring around 14 weeks after. This is a normal part of the canine estrus cycle; however, in some bitches the signs become extreme, causing what is called clinical or overt pseudopregnancy.

Mammary enlargement and milk production are the most common signs of overt pseudopregnancy, but other signs include enlarged abdomen, nesting behavior, decreased activity, aggression, and maternal behavior often aimed at inanimate objects. Some bitches even appear to go into labor, complete with abdominal contractions. The more convincing cases cause accusations of "who let the dog out?"

Usually, nobody. This convincing charade occurs because intact bitches undergo the same hormonal changes during diestrus whether they were bred or not. There's some evolutionary support for the idea that having related bitches available as a milk reservoir and nanny service would be beneficial enough to select for this ability. Exactly what causes it, and why it is more pronounced in some bitches than others, is not totally understood, but it basically can be traced to the hormones progesterone and prolactin.

Page 1 | 2 | 3