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Dystocia in Dogs

Dystocia is the medical term used to diagnose a difficult birthing experience. This condition may occur as a result of maternal or fetal factors, and can occur during any stage of the labor. Abnormalities of presentation, posture, and the position of the fetus within the uterus can negatively affect the temporal relationship between the birthing offspring and the maternal birth canal.

Uterine inertia (inactivity) may be primary or secondary. Primary inertia is symptomized by a failure of the body to commence synchronous uterine contractions, and secondary inertia is symptomized by a cessation of uterine contractions due to uterine fatigue. This latter condition sometimes occurs when labor has gone on longer than the uterine muscles are capable of meeting the demands for.

There are three stages of labor. The first stage of labor entails the start of uterine contractions, relaxation of the cervix, and rupture of the chorioallantoic sac (water breaking). The female dog (bitch) may be restless, nervous and occupy herself in nesting activity.

The second stage of labor is when the fetuses are pushed out by uterine contractions. In dogs the average length of parturition (delivery), from the beginning of stage two to delivery of the first offspring is usually less than four hours. The time between deliveries of subsequent offspring is usually 20–60 minutes, but may be as long as 2–3 hours. It is important to consider this variability before intervening.

The third stage is delivery of the fetal membranes. The female dog may alternate between stage two and three with multiple fetuses being delivered. She may deliver one or two fetuses followed by one or two fetal membranes, or she may deliver a fetus followed by its accompanying fetal membrane.

Symptoms and Types

Symptoms of dystocia:

• More than 30 minutes of persistent, strong, abdominal contractions without expulsion of offspring
• More than four hours from the onset of stage two to delivery of first offspring
• More than two hours between delivery of offspring
• Failure to commence labor within 24 hours of the drop in rectal temperature - below 99° F (37.2° C)
• Female cries, displays signs of pain, and constantly licks the vulvar area when contracting
• Prolonged gestation – more than 72 days from the day of first mating; more than 59 days from the first day of cytologic diestrus (the stage directly following the stage when conception would have occurred – can be determined by owner with vaginal swabs that are taken throughout pregnancy); more than 66 days from LH peak (luteinizing hormone, which peaks at the time of ovulation); (See Breeding, Timing)
• Discharge of uteroverdin from the vagina (a greenish-black pigment that is produced by the dog's placents), preceding the birth of the first offspring by more than two hours – indicative of premature placental separation
• Presence of bloody discharge prior to delivery of the first offspring or between fetuses
• vaginal wall to elicit abdominal straining [feathering]); the lack of this response indicates uterine inertia

Causes

Fetal

• Oversize fetus
• Abnormal presentation, position, or posture of fetus in the birth canal
• Fetal death

Maternal

• Poor uterine contractions
• Ineffective abdominal press
• Inflammation of the uterus (usually caused by infection)
• Pregnancy toxemia, gestational diabetes
• Abnormal pelvic canal from previous pelvic injury, abnormal conformation, or pelvic immaturity
• Congenitally small pelvis
• Abnormality of the vaginal vault
• Abnormality of the vulvar opening
• Insufficient cervical dilation
• Lack of adequate lubrication
• Uterine torsion
• Uterine rupture
• Uterine cancer, cysts or adhesions (due to previous inflammation)

Predisposing Factors to Dystocia

• Age
• Brachycephalic and toy breeds
• Obesity
• Abrupt changes in environment before dog goes into labor
• Previous history of dystocia

Diagnosis

You will need to give a thorough history of your dog's health, including any information you have about your dog's lineage, and details of any past pregnancies or reproductive problems. Your veterinarian will palpate (examine by touch) your dog's vaginal canal and cervix.

Your veterinarian will take samples for testing; at the minimum, a packed cell volume (PCV), a total protein, a BUN (blood urea nitrogen), a blood glucose, and a calcium concentration measurement. Your dog's blood progesterone levels will also be measured.

X-rays are crucial for determining the approximate number, size and location of the fetuses. X-rays may also show if the puppies are still alive, but an ultrasound can give even more subtle measurements, such as indications of fetal stress, assessing placental separation, and the character of the fetal fluids.