MANEJO REPRODUCTIVO EN HEMBRAS CON GESTACIÓN NO DESEADA

Para establecer el estado de preñez en una hembra que fue servida en una cópula no deseada se tiene que tomar en cuenta varios factores:

1.- Determinar la presencia de espermatozoides en la cavidad vaginal (permanecen en el tracto vaginal posteyaculación de 24 a 72 hrs. pero aún sin la presencia de éstos ya ingresaron al útero)..

2.- Determinar por citología vaginal si se encuentran mayoría de células cornificadas.

3.- Una hembra puede aceptar la cópula incluso sin estar ovulando.

4.- Si la hembra no va a ser destinada para la reproducción realizar la ovario-histeroctomía.

ESTRATEGIAS A REALIZAR EN CASO DE ESTAR PREÑADA

Cuando se sospecha que la perra tiene una preñez no deseada considerar los siguientes aspectos.

1.- Momento en que sucedió la cópula.

2.- Edad y peso de la perra.

3.- Cultivos para microorganismos en la vagina.

4.- Realizar ultrasonido si no se tiene el día de la cópula y presenta aumento del tamaño de las tetas.

Treatment of Undesired Matings with Pregnancy Termination in Dogs

Several medications have been used to terminate unwanted pregnancies, although no one drug has been found to work in all cases. Your pet may receive medication to terminate a pregnancy and still deliver a litter. Even though many dogs have successfully received these drugs and have had no complications, there is the potential for significant side effects. You may want to discuss allowing the dog to carry the pregnancy to term and deliver the babies in order to avoid the side effects of the medication.
Three primary classes of drugs have been used in pregnancy termination: estrogens, prostaglandins and glucocorticoids.

Estrogens for Pregnancy Termination in Dogs

These drugs work by preventing fertilized eggs from migrating and implanting in the uterus. The only way these drugs work is to give them soon after the unplanned breeding. Pregnancy cannot be confirmed at this stage and by giving this drug, your pet may be susceptible to dangerous side effects unnecessarily. These include:

Bone marrow suppression. This condition results in severe anemia, low white blood cell levels and low platelet counts. It can occur within two weeks to two months after administration of the drug and is typically irreversible and eventually fatal.

Pyometra. This uterine infection is another side effect of estrogen administration. Typically, this infection is not effectively treated with antibiotics and spaying may be required.

Infertility. Although this may occur following administration of estrogens, the exact reason is still unknown.
The most commonly used estrogens are:

Estradiol cypionate (ECP)

Diethylstilbestrol (DES). The injectable form of this drug has recently been removed from the market. The oral form is not effective in terminating pregnancy.

Prostaglandins for Pregnancy Termination in Dogs

In order to maintain a pregnancy, the hormone progesterone is required. This class of drugs works by reducing the levels of progesterone, which results in pregnancy termination. This drug is used after pregnancy has been confirmed. It is possible that your dog will not be sensitive to the prostaglandins and these drugs may not work. It is strongly recommended that your pet be hospitalized during prostaglandin treatment, which may four to seven days. This class of drugs is safer than estrogens and preferred by many veterinarians.
The most serious side effect of prostaglandin administration is the potential for pyometra, a uterine infection. Typically, this infection is not effectively treated with antibiotics and spaying may be required. There have been no reports of infertility associated with administration of prostaglandins.
An adverse effect of prostaglandins is the potential of failure to terminate the pregnancy or to terminate only part of the litter. Abdominal ultrasound is recommended to confirm complete pregnancy termination.
Commonly used prostaglandins to terminate pregnancy are:

Cloprostenol

Lutalyse (PGF)

Glucocorticoids for Pregnancy Termination in Dogs

This class of drugs only works on terminating pregnancies in the late stages of gestation and it not consistently effective. The way these drugs work to terminate a pregnancy is not fully understood. By terminating in the late stages of pregnancy, the aborted babies are typically expelled from the uterus. This can be traumatic for the dog as well as the owner. Temporary side effects associated with glucocorticoids are limited to increased thirst and increased urination after the treatment has ended. The most commonly used drug is dexamethasone.