Principles of Obstetrics Flashcards by Giselle Carter

what are some maternal causes of dystocia (5)

1) abnormal pelvis size or fracture
2) abnormal cervix (ringwomb)
3) uterine prolapse
4) uterine inertia
5) uterine torsion

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what commonly causes failure of cervical dilation in:
1) sheep
2) cows

1) ringwomb
2) uterine torsion, or dead calf

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how does ringwomb present in sheep and is there a genetic link

fetal membranes hanging from vulva; yes

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what is uterine inertia and what are primary and secondary causes

inability of the uterus to produce contractions

primary: hypocalcemia, overstretching (hydrops, multiple fetuses)

secondary: exhaustion of the myometrium after prolonged and unsuccessful delivery attempt

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what are some fetal causes of dystocia

1) fetal-maternal disproportion
2) fetal malalignment
3) multiple fetuses
4) fetal monsters

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what is the most common cause of dystocia in cattle and what breed is this most associated with

fetal-maternal disproprtion; double-muscled breeds like Belgian blue

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when does fetal-maternal disproportion commonly occur in dogs

when only a single pup that can grow too big for pelvis

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what is the most common cause of dystocia in horses (and alpacas)

fetal malalignment

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a calf is born with spinal curvature, unfused thoracic and abdominal walls and ankylosis

what is the diagnosis?

schistosomus reflexus

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a calf is born with vertebral agenesis and arthrogryposis, flexure and ankylosis of the hindlimbs, no vertebrae caudal to the thorax, and a flat pelvis

the front half is relatively normal

what is the diagnosis?

perosomus elumbus

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what is an autosomal recessive trait that is common in angus breeds

neuropathic hydrocephalus

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what equine breeds are commonly associated with hydrocephalus and why

Belgian and Friesian horses; autosomal recessive mutation in B3GALNT2

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what are 2 common causes of dystocia in dogs

1) fetal anasarca (associated with bulldogs)
2) fetal ascites (associated with organ abnormalities)

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what is the most common cause of dystocia in cows

fetopelvic disproportion

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what is the most common cause of dystocia in mares

fetal malalignment (most commonly head or limb deviation)

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what is the most common cause of dystocia in the bitch

uterine inertia

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what is the most common cause of dystocia in the queen

uterine inertia

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what is the most common cause of dystocia in the ewe

fetal malalignment (often complicated with multiple fetuses)

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what is the most common cause of dystocia in the ewe

fetal malalignment

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what is the most common cause of dystocia in the sow

uterine inertia, followed by fetal malalignment

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what three terms are used to describe the fetal alignment

presentation
position
posture

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presentation describes

the relative association of the long axis of the fetus with the maternal birth canal

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what is normal presentation

anterior longitudinal (posterior longitudinal also normal in cows)

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how can you tell whether the fetus is presenting in anterior or posterior longitudinal

anterior: the fetlock and carpus joints bend in the same direction

posterior: the fetlock and hock joints bend in opposite directions

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what is an additional test besides palpation of joints that you can use to determine the presentation

anterior: palmar aspects of hooves point down; feel for head posterior: plantar aspects of hooves point up; feel for tail **unless the fetus is upside down, always use palpation first**

T/F posterior presentation is normal in cows but usually requires assistance

what is position

describes the surface of the maternal birth canal to which the dorsal aspect of the fetus is aligned

what is normal position

dorsal-sacral

what is posture

describes the disposition of the fetal head, neck and limbs

what is normal posture

extended neck and limbs

what is normal presentation, posture and positioning (use horses as an example)

anterior longitudinal, dorsal sacral, extended head and limbs

describe breech

posterior longitudinal with bilateral hip flexion

describe two types of abnormal presentation

transverse (dorsal or ventral) and vertical (dog sitting)

a mare is foaling and delivery appears normal (two toes and a nose) and then suddenly stops what do you expect is happening

the baby is malpositioned and is in vertical presentation (dog sitting)

what is abnormal position

dorso-pubic; right or left dorsal-ilial

what are some examples of abnormal posture

lateral deviation of the head and neck; uni or bilateral carpal flexion, ventroflexion of the head (vertex); uni or bilateral shoulder flexion

what abnormal posture commonly causes rectovaginal fistulas

foot nape

T/F breech and posterior longitudinal, dorso-sacral with bilateral hock flexion are the same thing

F breech: posterior longitudinal, dorso-sacral with bilateral hip flexion not the same as bilateral hock flexion

you are presented a mare with dystocia and all you can see is the foals head what is the likely posture of the foal

we know the foal is anterior longitudinally presented and dorso-sacral position posture could be either bilateral shoulder flexion or bilateral carpal flexion

what do you want to assess on your initial exam of a dystocia

1) history (gather on way to farm) 2) general physical exam 3) cervix dilation 4) torsion? 5) fetal viability 6) fetal number 7) uterine tears 8) pelvic size/abnormalities 9) presentation, position and posture

what is the rule of 3

must see two limbs and a head present to pull

when dealing with dystocia we want to be as ________ as possible and be as ________ as possible

be as aseptic as possible and be as lubey as possible

where do you give an epidural in large animals with dystocia

sacro-coccygeal or C1-C2

why do we give epidural

reduces straining to help with extraction of the fetus (may result in more work for us though as we will need more assistance)

what lube do you NOT want to use in a dystocia and why

polymer lube; it is linked to acute deaths, and if it goes peritoneal causes hemolysis, peritonitis, renal failure and death

how do we most commonly assess fetal viability

fetal reflexes, also heartbeat, ECG or ultrasound can be used

how do fetal reflexes dissapear

from peripheral to central

how do we test fetal reflexes

1) interdigital claw 2) swallowing 3) eyeball (disappears last)

what fetal reflex is not consistent

anal

what is diagnostic traction

when you bring the head and two limbs into the birth canal with chains and see if you can make progress

what are good signs when you perform diagnostic traction

- hooves out with straining and in when straining stops - fetlocks/hocks can be extended a hand's width past the vulva

what are bad signs when you perform diagnostic traction

1) prolonged labour and head still not in pelvis 2) head goes back in when you start pulling the legs 3) forelimbs crossed 4) volar surfaces of hooves directed medially

what are the 3 principles of fetal repositioning

1) control 2) repulsion 3) rotation

how do we use rotation to reposition the fetus

1) bring distal limb in medially 2) rotate joint laterally

how do you place calving chains

with a double half-hitch; one hitch above the fetlock, one below on the pastern

T/F the fetal hooves have protective structures so it is not necessary to use any additional caution on the hooves

F; need to cup to prevent damage as we are correcting

how do you prevent hiplock

rotate the fetus 45 degrees through the widest angle of the pelvis

what are the 4 options for resolution of dystocia

1) assisted vaginal delivery (standing) 2) controlled vaginal delivery (anesthetized) 3) fetotomy 4) c-section

how do we perform assisted vaginal delivery

1) correct position 2) deliver in a downward arc 3) walk fetus through birth canal one forelimb in front of the other

T/F assisted vaginal delivery can be performed with or without epidural and sedation

how much force is needed to deliver a calf

70kg

T/F controlled vaginal delivery can be performed with or without sedation or epidural

F: it is performed under general anesthesia

what is a benefit of controlled vaginal delivery compared to assisted vaginal delivery

you can have members of the team preparing for c-section or fetotomy while you are working on the CVD

when you are called to the field for a dystocia and do an initial evaluation you determine the foal is alive; what is your next series of steps and timeline

1) determine if the foal can be delivered vaginally (do diagnostic traction) 2) if diagnostic traction confirms foal cannot be pulled -> c-section 3) if diagnostic traction confirms foal can be pulled -> spend 10 minutes on assisted vaginal delivery 4) if assisted vaginal delivery does not work -> spend 15 minutes on controlled vaginal delivery 5) if controlled vaginal delivery does not work -> c-section

you are called in for a dystocia and on initial assessment determine the foal is dead. what is your next series of steps and timeline

1) may decide to move on directly to fetotomy if you perform diagnostic traction and the foal cannot be delivered vaginally 2) if diagnostic traction confirms vaginal delviery is possible -> spend 10 minutes on assisted vaginal delivery 3) if AVD fails -> spend 15 minutes on controlled vaginal delivery 4) if CVD fails -> consider C-section or fetotomy