2. & 3. General Parturition, Obstetrics, & Fetotomy

True or false: As parturition nears, pre-partum changes occur. These vary across species.

true

In domestic species, what initiates parturition?

the fetus

What hormone must decrease in order for parturition to occur?

progesterone

In domestic species, how many stages is parturition divided into?

3

What are the 3 stages of parturition?

1. I

2. E

3. E

1. initiation of myometrial contractions (removal of progesterone block)

2. expulsion of the fetus

3. expulsion of the fetal membranes (placenta)

What is significant about the duration of the stages of parturition?

it varies by species

What are the main mechanisms of parturition?

M
I
A

• maturation of the fetal hypothalamic-hypophyseal-adrenal axis

• increased fetal corticoids from the adrenal cortex

• activation/conversion of placental enzyme systems

What is involved in the mechanism of parturition that is the activation/conversion of placental enzyme systems?

D
I

• decreasing progestagens

• increasing estrogen precursors and estrogens

What are the other mechanisms of parturition?

I
R
P
U
R

• increased sensitivity of the fetal adrenal glands to ACTH

• relaxin (relaxation of pelvic ligaments)

• prolactin (part of the initiation of lactation)

• up regulation of oxytocin receptors in endometrium

• release of prostaglandin F2 alpha

________ must drop for parturition to occur.

progesterone

________ rises as parturition nears.

estrogen

What is stage 1 of parturition?

initiation of myometrial contractions (removal of progesterone block)

What occurs during stage 1 of parturition?

M
R
A
A
I
N
S
A
E
C
F
D

• myometrial contractions

• restlessness

• anorexia

• abdominal discomfort

• increased pulse and respiration

• nesting and or isolation from others

• shifting weight

• arched back

• elevated tail

• colic like signs

• fetus rotates itself in preparation for exit (in mare, ewe, and cow) and this initiates Ferguson’s reflex

• dilation of cervix

neuroendrocine reflex comprising the self-sustaining cycle of uterine contractions initiated by pressure on the cervix or vaginal walls that is an example of positive feedback

ferguson’s reflex

In Ferguson’s reflex, when the fetus puts pressure on the cervix/cervical canal, it stimulates the release of ________, which stimulates ________ ________. This pushes the fetus into the cervix/cervical canal, causing more pressure, thus more ________ release and so on.

oxytocin; uterine contractions; oxytocin

What is the stage 2 of parturition?

expulsion of the fetus

What occurs during stage 2 of parturition?

F
R
A
D

• fetus enters cervical canal

• rupture of chorionic membranes (chorioallantois)

• active controlled abdominal pressing

• delivery of the fetus

What is the stage 3 of parturition?

expulsion of the fetal membranes

What is the duration of stage 3 of parturition?

varies by species

What does PPP stand for?

presentation, position, posture

relationship of the spinal axis of the fetus to that of the dam and the portion of the fetus that is entering the birth canal

presentation

What is the normal presentation of a fetus?

longitudinal - cranial

What are the types of presentation?

L
T

• longitudinal - cranial or caudal

• transverse - ventral or dorsal

anatomic relationships of the dorsum of the fetus relative to the maternal pelvis

position

What is the normal position?

dorsosacral

What are the other position possibilities?

P
L
R

dorso:

• pubic

• left ilial

• right ilial

anatomic relationship of the fetal extremities to its own body

posture

What are the types of posture that are possible?

F
E
R

• flexed

• extended

• retained

What is important to remember when it comes to posture?

be specific about which joints are affected

What is the normal posture?

head and forelimbs extended

Overall, what is the normal PPP for parturition?

cranio-logitudinal, dorso-sacral, head and forelimbs extended

In dogs, what is considered normal PPP?

cranio or caudo-longitudinal, dorso-sacral, head and limbs extended

In equine, what is the normal PPP?

cranio-longitudinal, dorso-sacral or ilial, head and forelimbs extended

difficulty giving birth

dystocia

What are examples of different causes of dystocia?

F
A
M
F

• fetus too large or dam too small (feto-maternal mismatch) → very common

• abnormal presentation, position, or posture

• multiple feti

• fetal malformations

Dystocia is more common in ________ than ________.

primipara; multipara

Among the common domestic species, ________ pose the highest incidence of dystocia and ________ have the lowest incidence.

cattle; cats

While specifics vary across species, what are some general truths when it comes to dystocia management?

P
C
V
D
B
B
U
E

• physical exam of the dam

• clean the perineal area

• vaginal exam (assess fetal viability, number, PP, size)

• develop a delivery plan

• be clean

• be gentle

• use lots of lube for entry and delivery

• epidural

When it comes to dystocia management, what is the theriogenologist’s mantra?

be clean, be gentle, and use lots of lube

What are the types of lube available?

P
M
K
J

• petroleum

• methylcellulose

• KY jelly

• J-lube (polytheylene polymer)

What is the lube of choice?

methylcellulose

Which lube is fatal if introduced into the abdomen and causes toxicity with marked accumulation of eosinophilic granular material in the bladder, kidneys, and spleen?

J-lube (polyethylene polymer)

How is methycellulose lubricant available?

powder or liquid form

How should an epidural be given?

inject slowly and avoid repeat epidurals

True or false: Twenty gauge needles inserted through unclipped hair resulted in the least amount of hair contamination. Spinal needles inserted through unclipped hair transferred many long hairs into the joint space.

true

Removal of hair is not indicated for arthrocentesis with ________ ________ needles, but is recommended when using ________ needles with ________.

sharp injection; spinal; stylets

Where do you want to give your epidural and how?

find the most cranial moveable space with the bevel forward and a slight tilt to the needle

Why can the hanging drop technique be useful?

will suck drip down, allowing you to know you are in the space

What are aspects that are involved when it comes to post-epidural?

C
T
D
I

• careful coming out of stocks

• turn into paddock with good footing

• do not ship until the epidural wears off

• if need to repeat epidural, use less volume, as epidural space may be decreased, thus volume may move forward

What are the methods of correction and delivery?

A
C
F
C

• assisted vaginal delivery (AVD) → standing or laying

• controlled vaginal delivery (CVD) → anesthetized ± elevated that is common in equine

• fetotomy (dead fetus only)

• cesarean section

process by which the fetus is restored to a deliverable fashion

mutation

pushing the fetus out of the maternal pelvis into the uterine cavity (maternal abdomen) to enable correction of the abnormality and allows for more space to mutate

repulsion

turning the fetus on its longitudinal axis

rotation

turning the fetus on its transverse axis into a cranial or caudal presentation which is a rare presentation in cattle but is most commonly seen in draft breed horses

version

What is this PPP?

cranio-longitudinal, dorso-sacral, right forelimb flexed at the carpus (retained limb)

What is rule #1 when it comes to correction of a retained limb?

bring limb up midline and protect the uterus

What is seen here? How do you straighten the legs?

contracted tendons; impossible to straighten them

What PPP is seen here?

cranio-longitudinal, dorso-sacral, head extended, both forelimbs flexed at the shoulder (retention of both front limbs)

What PPP is seen here?

cranio-longitudinal, dorso-sacral, head and forelimbs extended, hindlimb flexed at the hip (presentation of one hind limb)

What PPP is seen here?

cranio-longitudinal, dorso-sacral, head and forelimbs extended, hindlimbs flexed at the hips (dog sitting)

What PPP is seen here?

cranio-longitudinal, dorso-sacral, head flexed right, both forelimbs extended (flexed neck/head retained)

What are ways to hold onto the head?

N
F
E
N
N

• nose hold

• fingers in mouth (intermandibular space)

• eye socket holds (blunt eye hooks)

• noose around lower jaw

• noose around head that passes through opening of mouth

Wry neck is the same as a flexed neck, however, it is ________ to correct since the spine is ________ in this position.

impossible; fixed

How do you deliver a wry neck fetus? Why?

fetotomy or C-section may be necessary; not agreeable with life

What PPP is seen here?

caudo-longitudinal, dorso-sacral, hind limbs flexed at the hip (breech)

What PPP is seen here?

caudo-longitudinal, dorso-sacral, hind limbs flexed at the hock and stifle (hock presentation)

What is the PPP seen here? Why is this being pointed out?

caudo-longitudinal, dorso-pubic, hind limbs extended (rear feet pointed down); when down, likely cranio-longitudinal but can be backwards and upside down

What is this PPP?

dorso-transverse

What is this PPP? What is important to make sure of with this?

ventro-transverse; that you’re not feeling twin legs

What else is accompanied with a ventro-transverse PPP?

V
F

• ventral displacement of uterus

• folding of the uterus/cervix

What are the presentations when it comes to twins?

B
B
O

• both anterior

• both posterior

• one anterior, one posterior and vice versa (differentiate from dog sitting)

When pulling the fetus, what will traction on both forelimbs simultaneously often result in? Therefore, how should they be pulled?

shoulder lock; traction on one forelimb/hindlimb and then the opposite forelimb/hindlimb should be applied

How can you prevent hiplock?

rotate calf as fetal head emerges from the vulva

What part of the fetus are the widest part?

hips (wider than dam’s pelvis)

Why is rotation helpful when it comes to hiplock?

allows the hips (greater trochanters) more space

What are the types of fetotomy?

partial and full

Which type of fetotomy is most common?

partial

True or false: A partial fetotomy can be as little as one cut and can include the amputation of the head, neck, or limbs.

true

What are indications for a partial fetotomy?

F
F

• fetal malposture

• fetal oversize

What is involved in a full fetotomy?

5-6 specific cuts

What presentation is typically seen when a full fetotomy is indicated?

cranial

What are the typical steps in a full fetotomy?

D
A
D
D

• decapitation or cervical/vertebral amputation (one cut)

• amputation of forelimbs (two cuts) → subcutaneous or percutaneous

• detruncation (one or two cuts)

• division of the pelvis (must be divided diagonally and can be done in one cut)

What is involved in detruncation?

T
E
D
L

• transection

• evisceration

• destruction of the rib cage

• lumbar transection

True or false: Can be time consuming and takes a certain amount of stamina.

true

Where does detruncation transection occur?

right behind front limbs

Where does lumbar transection occur?

right in front of hind limbs

Should you cut above or below the hock? Why?

below; easier to grab and pull the fetus out