Dystocia Diagnosis & Management

It is imperative to understand the difference between normal whelping and dystocia. The following criteria are useful for this purpose, as well as indications for medical and surgical management.

Related Article: Dystocia in the Bitch

Criteria Indicating Dystocia

No matter the cause, dystocia is considered a true medical emergency. Breeders should contact their veterinarian under the following conditions:

1. Gestation length >67 days from the LH surge (or initial rise in progesterone from baseline), 65 days from ovulation, 59 days from day 1 of diestrus or >72 days from last breeding

2. >4 hours between rupture of the first chorioallantois—the expulsion of a non-odorous fluid that is tan or yellow in color—and delivery of the first puppy

3. >30 minutes of abdominal straining without delivery of a puppy

4. >2 hours between delivery of subsequent puppies

5. Any significant green and/or black discharge before delivery of the first fetus or increasing/large amounts of green and/or black discharge without signs of strong uterine and abdominal contractions. Typically, the presence of green and/or black discharge indicates the start of placental separation, so if any of this discharge is noted, abdominal contractions should be evident and the fetus delivered in a relatively short period of time (<1 hour).  If the amount of discharge continues to increase, without delivery of a fetus in 15-30 minutes, assistance should be obtained. After delivery of the first fetus, green and/or black discharge is normal since delivery of the fetal membranes usually accompanies fetal delivery.

6. Significant amount of bright-red bloody discharge at any point during delivery

7. Bitches with acute abdominal pain, excessive hemorrhage, or distracted mothering behaviors

Related Article: Cesarean Section in the Dog

Initial Examination

On presentation, the bitch should be placed in a quiet room with bedding and a heat source (if possible). There should be a warmed box or incubator for the puppies. A brief history should be taken to include reproductive history, behavioral changes, prior history of dystocia, and any pertinent health issues. A complete physical examination should be completed with attention to heart and respiratory rate, mucous membrane color, CRT, and pulse quality. Vaginal examination should be performed to determine presence of a fetus, fetal membranes, vaginal strictures, or a septum and to evaluate Ferguson’s reflex. Ferguson’s reflex can be demonstrated by feathering of the vagina using a firm, backward stroking of the dorsal vaginal wall using an index finger. Ferguson’s reflex is a neuroendocrine reflex that initiates abdominal contractions due to the presence of a fetus in the pelvic canal to aid in timely expulsion.

Ultrasonography can be used to determine viability using fetal heart-rate, and to assess placental integrity, and the character of fetal fluids (increased density indicates fetal stress). Abdominal radiographs are necessary to determine if there is obstruction caused by fetal positioning, as well the overall litter and fetal size. Blood glucose, ionized calcium, and urine ketones may be indicated.

Management

Criteria for medical management include:

• Stable condition, normal stamina

• No fetal obstruction

• Fetal HR >190 bpm

• ≤4 remaining fetuses. Larger numbers of fetuses may require excessive amounts of time and medication to deliver thus resulting in greater risk of fetal mortality.  Each dose of oxytocin administered results in decreased placental blood supply, so with larger numbers of fetuses, fetal hypoxia may result, followed by fetal death.

If a there is a weak or nonexistent Ferguson’s reflex, hypocalcemia or hypoglycemia may be present. Hypoglycemia should be treated with IV 5% dextrose in a balanced electrolyte solution. Hypocalcemia is treated with 0.2 mL/kg 10% calcium gluconate IV or SC. IV administration should be performed slowly while monitoring for arrhythmia. Calcium may be repeated q4–8h as needed. Once hypocalcemia is treated, if a fetus is not delivered within 30 minutes, oxytocin therapy should be instituted. Oxytocin should be administered in microdoses starting at 0.5–2 IU/bitch SC, IM, or IV, up to a maximum of 4 IU/bitch. The dose can be repeated at 30-minute intervals. If a fetus is not born after 3 doses or fetal heart rates begin to decline, C-section should be initiated immediately. Higher doses of oxytocin and/or multiple repeated doses may result in excessive uterine fatigue or tetany, which can cause fetal death.