Ex 3 - Canine Obstetrics

Question 1

Describe normal parturition in canines

Answer 1

fetal stress inc releases of CRH –> inc ACTH –> inc cortisol

cortisol causes placental synthesis of PGF2a –> this converts P4 to E2, thus overall dec of P4

E2 and PGF rise –> myometrium becomes more active –> CONTRACTIONS (P4 block is removed)

Cervix softens and dilates –> placental attachment is disrupted

Question 2

How many stages of parturition are there in dogs?

Answer 2

3

Question 3

Stage 1

Answer 3

uterine contractions –> complete cervical dilation

CS: anorexia, restlessness, panting, shivering, “nesting”

duration: 6-12 hrs
* nervous, primiparous bitches can experience up to 36 hrs of stage 1 (we should be concerned around 24 hrs)

Question 4

Stage 2

Answer 4

puppies moving through birth canal

usually delivered q30-60mins

up to 3-4 hours between babies can be normal

stage 2 is usually complete in 6 hrs, but can take up to 24 hr

Question 5

Stage 3

Answer 5

expulsion of fetal membranes

usually occurs during stage II in dogs (fetal membranes pass after each puppy, or within 15mins)

retained fetal membranes are RARE in the canine

Question 6

Dystocia

Answer 6

abnormal parturition

common in the canine ~5%
obvi - 100% in some breeds (e.g. bulldogs - all born via c section)

Question 7

Primary uterine inertia

Answer 7

failure of uterus to begin labor at full term

1. uterus fails to respond to fetal signals –> insufficient signals to initiate labor
   e. g. small litters, lg litters that stretch the myometrium, inherited predisposition
2. incompletely dilated cervix

Question 8

Secondary uterine inertia

Answer 8

contractions fail to expel fetuses –> muscles begin to fail

caused by obstruction of the birth canal

Question 9

Sequelae to secondary uterine inertia

Answer 9

delayed uterine involution –> SIPS (sub-involuted placental sites)

• bleeding/spotting after delivery

Question 10

Fetal factors that cause dystocia

Answer 10

3 P’s - 40% of dogs are born caudal longitudinal (“breech”)

abnormal fetal development

Question 11

How do we diagnose dystocia?

Answer 11

uterine monitors
prolonged gestation (look on SG for specific days)
systemic illness (sepsis, toxemia, etc)
**Stage II abdominal (hard) contractions w/no puppy delivered in 30 mins = dystocia!!
**Stage II weak contractions w/no puppy delivered in 2-3 hrs
partial birth
delivery of dead fetus
fetal distress

Question 12

Patient eval - straight forward

Answer 12

Hz, PE, abd rads, US, Doppler, BW

P4 levels:
- <2ng/ml is insufficient to support pregnancy

• 5.0ng/ml or greater is consistent with functional CL

Question 13

Treatment

Answer 13

IV cath and 1/4 shock fluid bolus + O2

Question 14

What is a “mild” case?

Answer 14

healthy bitch w/normal conformation, pups normal size and position, no evidence of obstruction or fetal distress, 4 or less pups remaining, weak/infrequent contractions

Question 15

When do we use Manipulative intervention?

Answer 15

Mild cases

bitch must be healthy

Question 16

When do we use medical intervention?

Answer 16

only if bitch has 4 or less pups remaining and the birth canal is unobstructed
- 27% chance of success
- Ca++ and oxytocin are the drugs of choice
(give oxytocin first then Ca++ if needed)

Question 17

What does administration of oxytocin do?

Answer 17

stimulates uterine contractions

*don’t give too much!

Question 18

What does administration of Ca++ do?

Answer 18

affects strength of uterine contractions

- monitor HR and rhythm with ECG

Question 19

What classifies “severe” cases?

Answer 19

obviously oversized fetus(es), evidence of fetal compromise, green/black/or bloody discharge w/no pup born in 20-30 mins, P4 < 2ng/ml for 24 hrs, obstructive dystocia of any causes. dystocia for any reason with 5+ pups remaining

Question 20

When is a C section indicated?

Answer 20

• bloody/green/black vaginal discharge
• no pup born in 20-30 mins
• Fetal HR < 150 bpm
• P4 levels < 2ng/ml for 12-24 hrs