Parturition and Obstetrics

Question 1

what are 5 options for pregnancy termination

Answer 1

-keep pregnancy and have litter

-spay

-aglepristone (alizin); only available through emergency drug release

-prolactin inhibitors; needs to be given after 30 days of pregnancy

-prostaglandins; causes luteolysis

Question 2

how do prolactin inhibitors work

Answer 2

prolactin is luteotropic (supports CLs) -> tx causes luteolysis -> progesterone levels decrease -> termination of pregnancy

Question 3

two names of prolactin inhibitors

Answer 3

cabergoline, bromocriptine

Question 4

how does aglepristone work

Answer 4

progesterone receptor antagonist, tricks uterus into thinking progesterone levels are low

Question 5

what do you need to be aware of if using prostaglandins to terminate pregnancy (how many injections, side effects)

Answer 5

-multiple injections needed
-side effects; hypersalivation, vomiting, diarrhea, micturition, panting, tachycardia (affects all smooth muscles)

Question 6

what are prostaglandins used in combination with and why

Answer 6

with algepristone or prolactin inhibitors. allows for lower doses and therefore less side effecs

if used alone its very hard on the bitch

Question 7

why is a mismate shot not recommended as pregnancy termination

Answer 7

high incidence of pyometra following treatment, bone marrow suppression also possible. never use it!

Question 8

what can you expect to see if there is pregnancy termination during early, mid and late gestation

Answer 8

-early; could see no outward signs of pregnancy termination (resorptions)

-mid gestation could see vaginal discharge; abortion (embryos/fetuses too small to see)

-late; could see actual fetuses; more difficult for clients to see this so it should be terminated before this point if possible

Question 9

what can you expect when P4 drops below 2ng/mL

Answer 9

labour beings in 12-36 hours

Question 10

what happens when P4 drops temperature wise

Answer 10

temperature…. drop by at least 1C to expect parturition

Question 11

what is the most common clinical sign of first stage labour

Answer 11

panting! sometimes its the only clinical sign present

Question 12

what happens during phase 1 of labour? how long does it last?

Answer 12

-synchronous uterine contractions; not visible from the outside

-cervical relaxation

-typically lassts 6-12 hours but can last up to 36 hours in primiparous bitches

Question 13

clinical signs during stage 1 of labour

Answer 13

◦ Anorexia
◦ Panting
◦ Shivering
◦ Restlessness
◦ Nesting
◦ Refusing to eat

Question 14

steps in fergussons reflex

Answer 14

◦ Fetus in birth canal → stretching cervix, vagina, uterus → oxytocin release

Question 15

what happens during stage 2 of labour

Answer 15

◦ Expulsion of fetuses
◦ Fergusson’s Reflex
◦ Visible abdominal contractions
◦ Allantochorion ruptures often during birth

Question 16

what often ruptures during birth (stage 2)

Answer 16

◦ Allantochorion ruptures often during birth

Question 17

what often covers pups at birth

Answer 17

◦ Allantoamnion often still covers pup at birth

Question 18

what is uteroverdin

Answer 18

◦ Breakdown product of biliverdin from placental margins

Question 19

what is normal timing for the entirety of parturition, and time between pups

Answer 19

◦ Usually 1 pup every 30 mins – 1 hr
◦ Can go up to 3-4 hrs between pups in some cases*
◦ Usually have all pups born within 6hrs but can go up to 24hrs in large litters

Question 20

what happens during stage 3 and when does it occur

Answer 20

◦ Passage of fetal membranes
◦ Occurs concurrently with stage 2

Question 21

how long should stage 3 take

Answer 21

◦ Can be passed with the puppy, or 5-15 mins after the pups
◦ Can have 2 pups before 1 placenta

Question 22

are retained placentas common in dogs

Answer 22

no they are rare

Question 23

what is presentation relating to and what is normal in dogs

Answer 23

◦ Relationship of spinal axis of the fetus to that of the dam
◦ Longitudinal vs transverse
◦ Longitudinal cranial/caudal = normal

Question 24

what is posture relating to and what is normal in dogs

Answer 24

◦ Relationship of the fetal extremities or the head/neck to the body of the fetus
◦ Extended head and limbs = normal

Question 25

what is position relating to and what is normal in dogs

Answer 25

◦ Relationship of the dorsum of the fetus in a longitudinal presentation, or the head of the fetus in a transverse presentation to the quadrants of the maternal pelvis ◦ Dorsosacral = normal

Question 26

risk factors for dystocia (5)

Answer 26

◦ Age of bitch (>6 years = associated with greater risk; especially if 1st litter) ◦ Parity (how many litters the bitch has had) ◦ Bitch breed ◦ Bitch weight ◦ Litter size

Question 27

is dystocia due to materal or fetal factors

Answer 27

can be due to either!

Question 28

what doesnt occur in cases of interia

Answer 28

no fergusson reflex occurs bc uterus fails to respond to oxytocin

Question 29

what happens with primary uterine inertia

Answer 29

◦ No sign of 2nd stage labor – never have delivery of a puppy ◦ Partial primary inertia = contractions start and stop without passage of a puppy ◦ Partial dilation of the cervix

Question 30

what are some causes of primary uterine inertia (4)

Answer 30

◦ Genetic (terrier breeds) ◦ Large litter – stretching of the uterus ◦ Inadequate stretching with 1-2 pup litters ◦ Hypocalcemia + other signs of systemic illness

Question 31

what happens with secondary uterine inertia

Answer 31

◦ Passage of 1 or more pups ◦ Prolonged uterine contractions fail to expel a pup

Question 32

what are some causes of secondary uterine inertia (3)

Answer 32

◦ Can occur for similar reasons as primary uterine inertia ◦ Can occur in large litters ◦ Can occur if a fetus is obstructing pelvic canal

Question 33

what are 3 general maternal factors for dystocia

Answer 33

-breed (brachycephalics) -conformation -maternal illness

Question 34

what are some materal issues related to confirmation that leads to dystocia (5)

Answer 34

◦ Persistent hymen ◦ Vaginal septum ◦ Tumors ◦ Vaginal prolapse ◦ Uterine torsion

Question 35

maternal illnesses that can lead to dystocia (2)

Answer 35

-parasitism -malnutrition

Question 36

general fetal factors leading to dystocia (3)

Answer 36

-presentation/posture/position -abnormal fetal development -fetal oversize

Question 37

types of abnormal fetal development that leads to dystocia (5)

Answer 37

◦ Abnormal number of limbs ◦ Thoracic/abdominal hernias, omphalocele ◦ Fetal monsters ◦ Hydrops fetalis/fetal anasarca ◦ Anencephaly

Question 38

how can fetal oversize happen

Answer 38

singleton litters

Question 39

issues related to presentation/position/posture that leads to dystocia

Answer 39

◦ Caudal longitudinal – failure to engage the cervix ◦ Breech

Question 40

when to communicate with the client when to call you (the vet)!!!!!! (11)

Answer 40

◦ Gestation length > known due date based on ovulation timing ◦ Gestation length > 70 days from breeding date ◦ >60 days from 1st day of cytological diestrus ◦ If haven’t whelped 24hrs past temperature drop = overdue ◦ If bitch is really straining for over 30 minutes with no pup produced ◦ Unproductive straining with pup in canal for >15 mins ◦ Weak, intermittent, abdominal contractions for >3 hrs without a pup; > 3hrs since birth of last pup ◦ Presence of lochia/uteroverdin & no signs of labor ◦ Stage 2 has been going on for longer than 18 hours (8-12 hours for valuable litters) ◦ Any sign of maternal distress or signs of maternal illness ◦ Any owner concerns

Question 41

steps in dystocia management (6)

Answer 41

-history -PE -fetal HR on ultrasound -rads -whelp wise -blood gas, CBC, biochemistry

Question 42

two aspects that must be included in the PE of dystocia management

Answer 42

◦ Including mammary gland evaluation – presence of milk? ◦ Vaginal palpation

Question 43

what does low fetal HR tell you on U/S

Answer 43

low HR = low oxygen

Question 44

what can rads tell you during dystocia cases (2)

Answer 44

◦ Fetal death ◦ Obstruction

Question 45

two parameters to look for from blood gas/CBC/biochem

Answer 45

◦ Glucose, calcium

Question 46

what % of dystocias result in C-sections

Answer 46

60-80%

Question 47

what three things are you trying to determine in dystocia management

Answer 47

* If there’s an actual pregnancy present? * What’s the cause of the dystocia? * Is there maternal or fetal compromise?

Question 48

medical management should only be considered IF (6)

Answer 48

* Bitch is in good health * Labor has not been going for too long * Cervix is dilated * Fetal size is appropriate * FHRs are normal * NO obstructive dystocia present

Question 49

what are ecbolic drugs

Answer 49

drugs that cause uterine contractions

Question 50

doses of oxytocin for medical management

Answer 50

0.5-2 U SQ q30 minutes

Question 51

doses of calcium for medical management

Answer 51

0.2mL/kg of 10% IV or 1-5mLs SQ

Question 52

what is the max amount of doses of oxytocin you can give to a dog for medical management of dystocia

Answer 52

no more than 2 doses!!!!

Question 53

when should you NOT use ecbolic drugs

Answer 53

never use in obstructive dystocias

Question 54

what does oxytocin do and what happens if too high of a dose is given

Answer 54

◦ Increases frequency of uterine contractions ◦ Uterine hyperstimulation & fetal distress + uterine tetany if too high a dose is given

Question 55

what does calcium do and how can you use it

Answer 55

◦ Increases strength of uterine contractions ◦ Calcium ions = necessary for myometrial contractions ◦ Can be used alone or with oxytocin ◦ Low levels and normal levels of calcium

Question 56

what do you need to ensure you do if you give calcium IV

Answer 56

give it SLOW and listen for arrythmias

Question 57

what to do with mechanical management

Answer 57

-lots of lube -digital manipulation; fingers are the best tool with cloth sponge -go with the ischial arch -instruments (spay hooks, sponge forceps, clamshell forceps)

Question 58

what do you need to be aware of with instruments and why

Answer 58

Very careful – can crush skulls, paws, quite easily

Question 59

5 indications for surgical management of dystocia

Answer 59

◦ Low fetal heart rate (<150bpm; sustained = emergency; 150-170bpm = moderate to severe fetal stress) ◦ Obstructive dystocia ◦ Primary & secondary uterine inertia ◦ Uterine rupture or torsion ◦ No response to medical management

Question 60

what do you always need to do prior to surgical management of dystocia

Answer 60

Always do a radiograph just prior to surgery to ensure there are still puppies to be delivered!!

Question 61

what is important to do with the mom during surgical management of dystocia

Answer 61

Important to stabilize mom (fluids, correct metabolic issues) if needed

Question 62

two goals of C sections in dystocia cases

Answer 62

◦ Want to minimize fetal respiratory, CNS and cardiovascular depression (Deliver live pups) ◦ Maximize mom’s anesthesia & analgesia (Limit complications for mom: hypotension, hypoventilation, hypoxemia, hemorrhage, hypothermia)

Question 63

5 things to consider for c sections

Answer 63

◦ Changes in bitch’s blood pressure (due to pain, stress, hyperventilation) → decreased blood flow to uterus → fetal hypoxia ◦ Bitches’ have increased oxygen consumption → increased risk of hypoxia → PRE-OXYGENATE!!! ◦ Increased blood flow to uterus → increased risk of hemorrhage ◦ Bitches’ are more likely to regurgitate under general anesthesia ◦ Most drugs that cross blood-brain barrier also cross placenta

Question 64

ideal c section drug protcols! (5)

Answer 64

* Pre-oxygenate mom * Induction with alphaxalone * Isoflurane or sevoflurane for inhaled anesthetic * Butorphanol for pain until pups are out, then hydromorphine * +/- epidural or local anesthetic

Question 65

best options for inhaled anesthetics for c sections

Answer 65

iso and sevo

Question 66

what do you NOT use during c sections

Answer 66

dont use tranquilizers and sedatives

Question 67

best c sections approach; how to do it, make sure you do what

Answer 67

Ventral midline ◦ Milk puppies through 1 uterine incision, might need more than 1 incision ◦ Make sure you palpate the entire uterus up to the ovaries

Question 68

why is c section spay approach not recommended

Answer 68

◦ Increased risk of hemorrhage & hypovolemic shock ◦ Lactation is normal ◦ Might be necessary in some instances; but not recommended

Question 69

why is en bloc approach to c section not recommended and how is it done

Answer 69

◦ Clamp uterine and ovarian vessels and ligate ◦ Remove entire uterus at once ◦ Risk – too slow → pups have no blood source ◦ Not recommended

Question 70

causes of fetal depression and what does it result in

Answer 70

◦ Due to hypoxia associated with dystocia ◦ Due to medications ◦ Results in slow HR, RR and movements

Question 71

goals of neonatal resuscetation center on what (2)

Answer 71

◦ Oxygen delivery to tissues (clearing airway) ◦ Warming the pup

Question 72

what does neonatal resuscitation include (5)

Answer 72

◦ Removal of fetal membranes and fluids from nose and mouth (Bulb syringe) ◦ Clamping of the umbilicus ◦ Rubbing puppies with warm towel – important to get them dry and warm ◦ Flow by oxygen as puppies start to gasp ◦ Naloxone (1-2 drops sublingual) if needed

Question 73

how should pups respond to neonatal resuscitation

Answer 73

Pups should respond to this by taking frequent breaths, turning pink and vocalizing

Question 74

what else can you try if normal steps in neonatal resusitation doesnt work (3)

Answer 74

◦ JenChung GV26 acupuncture point ◦ O2 mask ◦ Stimulating genitals for urination/defecation

Question 75

what is usually prescribed in practice for c section post op meds

Answer 75

TRAMADOL ◦ Little effect to neonates that are nursing (based on human medicine) ◦ What is typically prescribed in practice ◦ Efficacy is controversial (dogs produce more of the weak analgesic metabolite; half life of good metabolite is very short)

Question 76

when do canine kidneys mature and function normally

Answer 76

◦ Canine kidneys → maturation doesn’t occur until 3 weeks of age; normal function at 6-8 weeks of age

Question 77

does one c section make a dog predisposed to another c section in the future?

Answer 77

◦ Increased chance of requiring a c-section if they’ve had 1 already ~~Depends on the cause of requiring the c-section in the 1st place (Singleton litter vs uterine inertia, Predisposition to uterine inertia increases the chances of requiring a 2nd c-section?) ◦ Usually if they’ve had 2 → I recommend the third to be an elective

Question 78

things to look for to determine if fetuses are ready for birth (2)

Answer 78

◦ Presence of milk ◦ Should ask owner regarding any signs of 1st stage labor

Question 79

why is it important to determine if puppies are ready to be born (2)

Answer 79

◦ Premature puppies have a high mortality risk ◦ Canine placenta cannot support fetuses >2 days past whelping date → intra-uterine fetal death

Question 80

ultrasound findings to determine if puppies are ready to come out (5)

Answer 80

◦ Signs of fetal distress (FHRs are taken) ◦ Appearance of fetal kidneys → similar to adult appearance (Can distinguish cortex from medulla, Renal pelvises become less dilated at term) ◦ Appearance of fetal intestines → can distinguish between layers (serosa, mucosa, submucosa) ◦ Peristalsis is present @ term ◦ Biparietal diameter – anecdotal finding