Principles of Obstetrics

Question 1

what are signs of impending parturition

Answer 1

1. hormonal changes
2. mammary development
3. vulvar discharge
4. relaxation of peripelvic ligaments
5. temperatuer drop
6. behavior changes

Question 2

what hormonal changes occur prior to parturition (PGF2a, estrogen, progesterone)

Answer 2

1. high PGF2a
2. high estrogen
3. low progesterone

Question 3

eutocia

Answer 3

normal progression of labor

Question 4

stages of labor

Answer 4

1. stage 1
2. stage 2
3. stage 3

Question 5

stage 1 labor

Answer 5

• final positioning of fetus
• cervical dilation
• behavioral changes

ends with rupture of chorioallantoic membrane as the fetus enters the cranial vagina

duration: 1-24 hours

Question 6

stage 2 labor

Answer 6

• fetal delivery
• abdominal and uterine contractions

length of time to safely be in stage 2 labor varies by species

Question 7

duration of stage 2 labor in cows, mares, sows, dogs/cats

Answer 7

cows: 0-4 hours
mares: 10-30 minutes
sows: 1-5 hours
dogs/cats: 3-6 hours

Question 8

stage 3 labor

Answer 8

• expulsion of fetal membranes

complication: retained placenta
- mares: metritis, septicemia, laminitis
- ruminants: endometritis, metritis, infertility
- dogs/cats: metritis

Question 9

duration of stage 3 labor in cows, mares, sows, dogs/cats

Answer 9

cows: 1-12 hours
mares: 1-3 hours
sows: 1-12 hours
dogs/cats: 3-6 hours
- can alternate between stage 2 and 3 labor between puppies/kittens

Question 10

premature placental separation

Answer 10

common in HORSES

“red bag” - placenta starts coming through the vagina without rupture causing no support to fetus
- visible cervical star

need to cut open the red bag and remove the foal to allow it to breathe

Question 11

dystocia

Answer 11

difficult or abnormal parturition

always confirm the dam is in labor - check breeding date, confirmed pregnancy, expected due date

Question 12

clinical signs of dystocia

Answer 12

• failure to initiate stage 1
• failure to proceed to stage 2
• prolonged stage 2
• fetal or maternal distress
• abdominal contractions without progress
• unusual vaginal discharge (ex. biliverdin before first puppy)

Question 13

diagnostics for dystocia

Answer 13

• physical exam
• vaginal exam
• US
• radiographs
• uterine monitoring

tocodynamometry - measures uterine contractions in dogs

Question 14

fetal causes of dystocia

Answer 14

1. fetal maternal mismatch
2. mechanical abnormality
3. multiple fetuses and the same time
4. fetal or pregnancy pathology

Question 15

maternal causes of dystocia

Answer 15

1. primary uterine inertia
2. secondary uterine inertia
3. birth canal abnormalities

Question 16

primary uterine inertia

Answer 16

abnormal contractility prior to stage 2 (before active labor)

Question 17

secondary uterine inertia

Answer 17

abnormal contractility caused by fatigue/exhaustion during stage 2 labor (prolonged stage 2 without delivery)

Question 18

examples of birth canal abnormalities

Answer 18

small/irregular pelvis
incomplete dilation
uterine torsion

Question 19

common causes of dystocia in ruminants

Answer 19

• fetal-maternal mismatch
• postural abnormalities
• maternal metabolic disease

Question 20

common causes of dystocia in horses

Answer 20

• postural abnormalities
• fetal-maternal mismatch

Question 21

common causes of dystocia in pigs

Answer 21

• uterine inertia
• obstructive causes

Question 22

common causes of dystocia in dogs/cats

Answer 22

• uterine inertia
• obstructive causes
• fetal presentation

Question 23

what are mechanical abnormalities

Answer 23

presentation, position, posture

Question 24

presentation

Answer 24

long axis of fetus vs direction of travel
- cranial
- caudal
- transverse

Question 25

position

Answer 25

dorsum of fetus vs dams birth canal - dorso-sacral - dorso-pubic - dorso-iliac

Question 26

posture

Answer 26

relation of fetal extremities to the fetus (flexed neck, limbs, etc)

Question 27

true breech

Answer 27

- caudal - dorso-sacral - bilateral hindlimb flexion at the hips