Gynaecology and Obstetrics Section

Uterine inertia in Bitches

UTERINE INERTIA

Primary uterine inertia

• Failure of sufficient uterine contractions to expel the conceptus.

Secondary uterine inertia (Fetal obstruction)

• Due to large size fetus, narrow pelvis, vaginal strictures and abnormal fetal position.
• Brachycephalic breeds typically have a narrow (or) small pelvis. Small breeds are more often nervous and prone to single-pup litters. Large breed bitches have low incidence of dystocia problems.

Diagnosis

Dystocia should be suspected if

• After a birth of a puppy more than 4 to 6 h has passed without another birth/progresion in labour 
• A bitch failing to deliver pups 24 to 36 h after the rectal temperature was noted to decrease below 100°F.
• Strong abdominal contractions for 30-60 min without successfully expelling a puppy.
• A birth that has a prolonged gestation lasting beyond 70 to 72 days from the first breeding or beyond 60 days from the first day of diestrus

Use of breeding dates

• Using the first day of breeding, whelping can occur in normal bitches at any time between days 56 to 72 of gestation.

Physical examination of the bitch

• Abdominal palpation and vaginal examination should be carried out to assess the presence of fetus in the uterus and vaginal passage, respectively.

Radiography and / or Ultrasonography

In dystocia cases, radiography should be performed to identify the presence of fetuses, their number, location and to identify the malpositioned fetuses. Ultrasonography is diagnostic toll  for assessing fetal viability. Fetal death is likely if radiography shows

• Evidence of collapse of the spinal column
• Intra fetal gas patterns
• Misalignment of the bones
• Obviously abnormal fetal positioning

Radiographs also identify the presence of an obviously large single fetus and allow examination of the pelvic structure of the birth canal, possibly identifying an obstruction.

Treatment

• Manual Therapy
• Palpation of the cervix is not possible in the bitch. The vaginal vault is too small in most bitches to allow significant digital manipulation of the conceptus. Thorough lubrication, and if required use of whelping forceps will be helpful to deliver the pups.
• Medical Management
• Before choosing medical therapy, it should be ascertained that fetal (or) maternal obstructions are not present.
• Oxytocin is administered at the dose rate of 2 units per kg maximum of 20 units at a time as a slow intravenous drip.
• Wait for 30 minutes. If no progress in the delivery administer oxytocin at the same dose rate combined with 5-10 ml. of 10% calcium gluconate (Calcium sandoz) and 20 – 30 ml. of 20% dextrose intravenously.
• Again, wait for 30 minutes. If no progress, administer a second dose of injection of oxytocin, calcium and dextrose. If there is still no progress, cesarean section is advised.
• Cesarean section