Canine False Pregnancy (Pseudopregnancy, Pseudocyesis)

Non-pregnant female dogs commonly display physical and behavioural signs consistent with pregnancy. This is infrequent in female cats. The abdomen may appear somewhat swollen and milk may be produced in the mammary glands. This is associated with hormonal imbalances and ovarian abnormalities, but it can also occur in spayed females. Signs of false pregnancy may be subtle and unnoticed. The bitch may redirect maternal urges by carrying toys or other objects, presumably surrogate offspring, to a nest she has prepared. She may be restless and irritable. Aggressiveness may be more easily provoked during this period, perhaps because of hormonal imbalances, though other factors are certainly involved. False pregnancy may resolve without treatment, but recurrence is common in subsequent "heat" cycles and complications are common. Medication may or may not temporarily resolve false pregnancy. Unless the pet is of particular breeding value, pronounced false pregnancy justifies spaying.

Clinical False Pregnancy

When false pregnancy persists it can be a nuisance. The female dog can show the following signs:

• Nesting
• Mothering inanimate objects
• Lactating (giving milk)
• Abdominal distension
• She can even appear to go into labor

Some female dogs are very sensitive to the hormonal fluctuations of the cycle. Diagnosis is made by history and physical examination rather than by blood test. The key is to find symptoms of pregnancy in a female dog who is not pregnant. Symptoms generally become noticeable 6 to 3 months after estrus.

Treatment

If symptoms are mild, treatment is unnecessary as the condition resolves within 3 weeks. It may be tempting to put warm compresses on the breasts or wrap them to prevent milk leakage causing stains in the house. It is important to remember that any touching of the mammary tissue is what stimulates milk production, so it is important to minimize tactile stimulation. If the female is licking herself, she may need an Elizabethan collar to minimize stimulation. If a more aggressive approach is needed, a diuretic such as furosemide can be prescribed. The idea is that mild dehydration will end the lactation. Some people may want to try water deprivation but this is potentially dangerous and should not be attempted without specific veterinary guidance.If this doesn’t work, hormonal medications can be used. Progesterone can be used but after the course of medication is complete, the false pregnancy recurs so this is not a good choice. Estrogens are also not a good choice as they bring the dog back into estrus symptoms. A week’s course of the male hormone mibolerone has generally been successful but the medication is no longer available. Hormones that inhibit prolactin (the hormone of milk production) are currently the best choices when medications are needed. Bromocriptine can be obtained from a compounding pharmacy and given until lactation ceases (about a week or two) but tends to cause upset stomach. Cabergoline has fewer side effects but is given similarly and tends to be more expensive. Both these medications will cause abortion if the dog actually turns out to be pregnant so it is important to be sure.

Spay During False Pregnancy?

It might seem like a good idea to spay the female to end the false pregnancy as spaying will remove the ovaries and the corpora lutea they carry. Unfortunately, this does not end the prolactin production from the pituitary gland so spaying may actually prolong the false pregnancy. It is best to wait until the false pregnancy is over and then spay her to prevent future episodes.

Pregnancy Termination in Dogs

Accidents happen, and a large number of pets become pregnant despite their owner's wishes. In most cases, the best solution to this problem is to have the bitch or queen spayed, which will not only solve the current problem, but prevent it from happening in the future. Ovariohysterectomy during pregnancy, unless very close to term, does not pose significantly elevated risks to the animal over and above the standard surgery.
There are several situations in which it is desirable to terminate a pregnancy, yet retain the animal's ability to reproduce in the future. Examples would include a valuable purebred breeding bitch that is accidently bred by an "undesirable" dog, or a estrous bitch that the owner may want to breed in the future that is found cavorting with a neighborhood dog in the backyard!
Before discussing treatments for pregnancy termination, one point should be made: Just because an bitch in estrus is found together with a male doesn't mean they have already mated. In fact, it seems to be the case that a majority of bitches presented to veterinarians for "mismating" treatment are not pregnant.
One fairly reliable method of determining whether mating has indeed occurred is to examine a vaginal smear within a few hours, even up to a day, after the alleged liason occurred. If the dog was bred, one can almost always find sperm on the smear without much difficulty. Not finding sperm does not rule out mating, but suggests that it may well not have taken place, which can influence how the bitch is treated.

Estrogen Treatment for Mismating
A variety of estrogens have previously been recommended and used as treatments for mismating. Two of the most popular formulations have been diethylstilbestrol and estradiol cypionate (ECP). Interestingly, there is very little objective data to support either the safety or efficacy of these drugs for treating mismating in dogs, and essentially none in cats.
The few controlled studies that have been conducted indicate that estrogen therapy in bitches is associated with a high risk of inducing uterine disease such as pyometra and some risk of causing a lethal aplastic anemia. Additionally, the dosages of estrogen and timing of treatment that appear to minimize risk of these disease are poorly effective in preventing pregnancy. The impression that estrogen treatment is efficacious may be largely be due to the fact, mentioned above, that many bitches presented for mismating treatment have not actually been bred.
In summary, there is little doubt that estrogen therapy for mismating in bitches is not only unsafe, but often ineffective in preventing pregnancy.

Termination of Pregnancy with Prostaglandin F2alpha
Prostaglandin F2alpha (PGF, Lutalyse(R), dinoprost tromethamine) is a hormone that induces luteolysis in many species, including dogs. Because progesterone is necessary throughout gestation for maintenance of pregnancy, PGF-induced death of the corpus luteum leads to termination of pregnancy. PGF also has the ability to stimulate uterine contractions, which may contribute to its abortifacient activity.
The canine corpus luteum is essentially unresponsive to PGF prior to diestrus day 5, then becomes progressively more susceptible to luteolysis through gestation. As a consequence, lower doses of PGF are required to induce abortion later in gestation.
PGF is administered twice daily, either for 4 days (less than 4 weeks of gestation) or until abortion is complete (after 4 weeks). In the later, case, the bitch should be monitored daily by palpation or ultrasound to evaluate whether abortion has taken place.
PGF treatment has a number of unpleasant side effects in dogs, including vomition, panting, cramps excessive salivation and defecation. These effects can be ameliorated to some extent by walking the animal immediately after treatment. Because of these adverse effects of PGF, treatment should be conducted in a veterinary clinic.
Two important precautions should be recognized with respect to use of PGF:
Women of childbearing age and people with asthma or other respiratory problems should use extreme caution in handling PGF solutions. This drug is readily absorbed through the skin and can cause uterine contractions and bronchospasm in exposed persons. This is another reason for conducting treatment of bitches in a clinic rather than by prescription.
PGF analogs such as cloprostenol are not approved for termination of canine pregnancy. They are very much more potent than PGF, and using an analog at the same dosage as PGF2alpha can be lethal.
PGF treatment is an effective treatment for termination of pregnancy in bitches. Properly administered, it is also safe and does not appear to have adverse effects on future reproductive performance of the bitch.
PGF can also be used to terminate pregnancy in cats, at least after day 33 of gestation.

Other Methods for Terminating Canine Pregnancy
Several other drugs have been investigated experimentally for terminating canine pregnancy, and while some show considerable promise, these treatments either are not currently available or cannot yet be recommended due to lack of data from clinical trials. Examples include:

• Dopamine agonists: Prolactin is necessary to support function of the canine corpus luteum, and secretion is inhibited by dopamine. Drugs such as bromocryptine and cabergoline, which bind to dopamine receptors in the pituitary gland, suppress prolactin secretion and can terminate pregnancy in dogs by suppressing progesterone secretion from the corpus luteum. Dopamine agonists are effective in terminating canine pregnancy only after about 25 days of gestation. Like PGF, they require repeated treatment and commonly induce vomition and inappetence.
• Epostane: This drug inhibits steroid hormone synthesis by inhibiting the enzyme that converts pregnenolone to progesterone. It has been shown to terminate pregnancy in dogs after a 7 day treatment and appears to have this effect throughout gestation. Further, adverse side effects in dogs have not been been reported.
• Mifepristone (RU486): This well-known drug acts as a progesterone antagonist. Small clinical trials have demonstrated that his drug is very effective in terminating canine pregnancy after 25-30 days of gestation, and without apparent adverse effects.

Clearly, several drugs appear to have promise as safe and effective abortifacients in dogs, and deserve additional research and marketing attention as aids for pet population control.

Mating in Dogs

Female dogs generally have 2 reproductive cycles each year. This process begins at puberty. Small breeds may start their cycles at 5-6 months of age, while some giant breeds may not cycle until 2 years of age. The average age of puberty is 7-10 months. After 4-9 days of bloody vaginal discharge, the female will accept the male and stand for breeding. This receptive stage may last a few days or as long as 2 weeks. The most commonly used breeding dates are the 9th, 11th, and 13th days from the first vaginal discharge. Repeated breeding 48 hours apart, as long as the female accepts the male produce the best conception rate.
Usually, no assistance is needed for a successful mating, especially if dogs have had previous experience. Occasionally, however, some assistance must be given. The male may need help in mounting and entering the female, or the female may need to be restrained so that she does not harm the male. A muzzle (gauze, nylon stockings, etc.) tied around the female's mouth may be helpful. If trouble is encountered, perhaps the timing is not correct. Double check the dates and consult with your veterinarian.
Near the conclusion of normal mating, the dogs will become "tied" together for up to � an hour. Occasionally, the male turns around and the dogs appear "end to end." This is normal and no cause for alarm. If one of the dogs becomes active during this time, gentle restraint is advisable. Do not attempt to forcefully pull the dogs apart, as this may cause injury.
Female dogs should not be bred during the first heat period. Wait until the second or third heat to breed your female.
Since pregnancy represents a considerable strain on the mother, females should not be bred every "season." Acceptable breeding programs include breeding every other heat or breeding during 2 consecutive heats and skipping the third.
If a pregnancy results from the mating, the puppies should be born in approximately 63 days. Begin counting from the first breeding.
If you are considered mating your dog, discuss the matter with your veterinarian. A thorough examination is recommended before breeding to help ensure that your pet is in good physical condition.

Heat Cycle (Estrus) in Dogs

Non-spayed female dogs will go into "heat" or estrus usually twice a year. The age at which they start their cycles and the duration of the cycle varies greatly between the breeds of dogs and individual dogs.

There are four stages to the canine estrus cycle:
Proestrus: vaginal discharge, males attracted to females, females unwilling to mate. Length: 4-20 days.Estrus: swollen vulva, yellowish vaginal discharge, mating occurs during this phase. Length: 5-13 days. Metestrus (or Diestrus): period after estrus or mating. Length: 60-90 days. If pregnant, pregnancy lasts between 60-64 days in the dog.Anestrus: period of inactivity (sexual and hormonal) between estrus phases. Length: 2-3 months.

Some general "rules of thumb" for canine estrus:
The first estrus cycle usually occurs by age 6-12 months; for some small breeds, as early as 5 months, and for some large and giant breeds, the first cycle may not occur until 14 months of age or older.
On average, dogs have two cycles a year.
The estrus cycle lasts on average 12-21 days, but maybe be as short as a few days to four weeks.

The estrus period length varies widely between breeds and individual dogs.
The length of a cycle varies widely, even for dogs of the same breed. If in doubt, assume the longer end of the range for the cycle length.
Bleeding occurs prior to a female being receptive to a male (allowing mounting by the male), but male dogs will be very attracted to the female in the proestrus stage.
Dogs can get pregnant during their first heat cycle, but this is not advisable as a 6-month old dog is not yet fully grown/mature, and complications for the mother and the puppies are more likely.
For dogs that will be pets, it is recommended to spay them before the first heat, eliminating the risk of accidental pregnancy and reproductive diseases later on in life. Dogs may be spayed while in heat (or pregnant), but there is additional risk due to the engorged vessels and tissue of the reproductive tract -- a higher chance of bleeding during surgery or other complications. The cost of surgery while in heat or pregnant is often higher as well.