Dystocia in Dogs
Dystocia, a medical condition, refers to a challenging birthing process in dogs. It can stem from issues with either the mother or the fetus and can occur at any point during labor. Factors such as abnormal presentation, posture, and fetal positioning within the uterus can disrupt the timing of the birthing process relative to the maternal birth canal.
Uterine inertia, characterized by a lack of activity, can be primary or secondary. Primary inertia involves a failure of the body to initiate synchronized uterine contractions, while secondary inertia occurs when uterine contractions cease due to muscle fatigue, often resulting from prolonged labor.
Labor in dogs occurs in three stages. The first stage involves the onset of uterine contractions, cervical relaxation, and the rupture of the chorioallantoic sac (commonly known as the water breaking). During this stage, the female dog, or bitch, may exhibit restlessness, nervousness, and engage in nesting behaviors.
The second stage of labor sees the expulsion of fetuses through uterine contractions. In dogs, the average duration of parturition (the delivery process) from the beginning of stage two to the birth of the first offspring is typically less than four hours. The interval between deliveries of subsequent offspring usually ranges from 20 to 60 minutes, though it may extend to 2–3 hours. It’s essential to recognize this variability before considering intervention.
The third stage involves the delivery of fetal membranes. The female dog may alternate between stages two and three while delivering multiple fetuses. She might deliver one or two fetuses followed by their respective fetal membranes, or she may deliver a fetus along with its accompanying membrane.
Symptoms and Types
Symptoms of dystocia include:
- Persistent, strong abdominal contractions lasting more than 30 minutes without the expulsion of offspring.
- A duration of more than four hours from the onset of stage two to the delivery of the first offspring.
- Intervals of more than two hours between the delivery of offspring.
- Failure to initiate labor within 24 hours of the drop in rectal temperature, which falls below 99°F (37.2°C).
- The female dog cries, exhibits signs of pain, and consistently licks the vulvar area during contractions.
- Prolonged gestation, defined as more than 72 days from the day of the first mating, more than 59 days from the first day of cytologic diestrus, or more than 66 days from the LH peak (luteinizing hormone, which peaks at ovulation).
- Discharge of uteroverdin from the vagina, a greenish-black pigment produced by the dog’s placenta, occurring more than two hours before the birth of the first offspring, indicating premature placental separation.
- Presence of bloody discharge before the delivery of the first offspring or between fetuses.
- Lack of response from the vaginal wall to elicit abdominal straining (feathering), indicating uterine inertia.
Causes
Causes of dystocia can be categorized into fetal and maternal factors:
Fetal:
- Oversized fetus
- Abnormal presentation, position, or posture of the fetus in the birth canal
- Fetal death
Maternal:
- Poor uterine contractions
- Ineffective abdominal press
- Uterine inflammation (often due to infection)
- Pregnancy toxemia and gestational diabetes
- Abnormal pelvic canal resulting 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 (resulting from previous inflammation)
Predisposing Factors to Dystocia include:
- Age
- Brachycephalic and toy breeds
- Obesity
- Abrupt changes in the environment before the dog goes into labor
- Previous history of dystocia
Diagnosis
Diagnosing dystocia involves obtaining a comprehensive history of your dog’s health, including details about its lineage and any prior pregnancies or reproductive issues. Your veterinarian will perform palpation, which involves examining the vaginal canal and cervix by touch.
Samples will be collected for testing, including a packed cell volume (PCV), total protein, blood urea nitrogen (BUN), blood glucose, and calcium concentration measurements. Additionally, your dog’s blood progesterone levels will be assessed.
X-rays are essential for determining the approximate number, size, and location of the fetuses. They can also indicate whether the puppies are alive. Ultrasound imaging provides more nuanced information, such as detecting signs of fetal distress, assessing placental separation, and evaluating fetal fluid characteristics.
Treatment
Dogs experiencing distress and diagnosed with dystocia should receive treatment as inpatients until all offspring are delivered and the mother stabilizes. If uterine contractions are absent and there’s no sign of fetal stress, medical intervention will commence. Potential causes include low blood sugar, low blood calcium levels, insufficient oxytocin production, or an inadequate response to normal oxytocin levels.
Agents promoting uterine contractions shouldn’t be administered if obstructive dystocia is suspected, as they may accelerate placental separation, fetal demise, or uterine rupture. Oxytocin, glucose, and calcium supplementation may be necessary.
Manual delivery might be required to extract a fetus lodged in the vaginal vault. Veterinarians employ digital manipulation to reposition the puppy, minimizing harm to both puppy and mother. In cases where the vaginal vault is too narrow, instruments like a spay hook or non-ratcheted forceps may assist delivery. Throughout, lubrication is used, with a finger guiding instruments to protect both mother and puppies.
Extreme caution is warranted to avoid complications such as fetal mutilation or damage to the vaginal canal or uterus. Traction should never be applied to the limbs of a live fetus. If delivery isn’t achieved within 30 minutes, a Cesarean section is necessary.
Living and Management
For breeds prone to dystocia or those with a history of the condition, consult your veterinarian regarding the option of scheduling an elective cesarean section before labor begins. Timing is critical to safeguard the health of both the mother and puppies. If dystocia is suspected early in labor, promptly contact your veterinarian to prevent complications for the mother and puppies.