parturition Flashcards
dogs and cats have what kind of placenta
zonary
zonary placenta
between the placenta and the allantochorion a natural accumulation of blood develops. This blood turns dark green in the dog and brown in the car
this is referred to as the marginal haemotoma
pregnancy detection
conceptuses can be imaged with ultasound from day 12, but easiest around 3-4 weeks
abdominal palpation 2-5 weeks
relaxin assay - from 4 weeks, hormone released from placenta
day 45 clinical exam by MRVCS recommended
pregnancy diagnosis who can diagnose?
vet only
feline and canine pregnancy diagnosis
auscultation
possible to detect foetal heart beats in latter stages. HR’s of less than 150bpm can mean foetal distress and warrants investigation
stages of parturition
- first stage (onset contractions)
- Second stage (propulsion of foetus)
- Third stage (passage of placenta)
Parturition aetiology
precise aetiology of parturition not known but generally believed that foetal distress is the initial cause
the release of foetal glucocorticoids
stimulates the release of pgf2alpha from placenta
this initiates corpora lutea regression leads to decline in progesterone - causing a sudden drop in temp
-
preparation stage
in last week of pregnancy its recommended to record the dam’s rectal temp at least twice daily
this is to detect the prepartum hypothermia that precedes the onset of parturition by 24-36hours
canine behaviour - nestling, restlnessness,
feline behaviour - most seek seclusion during this stage
first stage parturition
initial weak contractions that orientate cervix
cervix starts to dilate
relaxin
lasts 1-12hours
bitches become restless
cats seek seclusion
second stage of parturition
foetal birth
once first foetus has entered the pelvic canal, the ferguson relfex is initiated triggering the release of a hormone that causes contractions
oxytocin - which strengthens the uterine contractions and causes the propulsion of the foetus through the cervix into the vagina
second stage of parturition
during this time allantochorion membrane is usually ruptured causing a clear vulval discharge
commonly 10-30 minutes sometimes longer in primiparous bitches (fist time mothers)
second stage parturition
a membrane, the amnion, surrounds the foetus
the dam will usually remove this membrane and eat the placenta. bitch should be discouraged from eating this
if the dam fails to remove membranes immediately after birth, it must be done for her swiftly
second stage
puppies should be checked for
breathing
airways clear
cleft palate
anus/genitalia present
weight
sex recorded
distinguishing markings
Third stage parturition
the birth of the foetus is usually followed by the passage of the allantochorion and placenta
after a bitch has finished whelping, there is normally a dark coloured vulval discharge
contains green pigment that originates from marginal haematoma
in cats the discharge should normally decline after a week
Dystocia
dystocia - difficulty giving birth
rare in the queen but not in brachycephalic dogs
two main causes of dystocia - maternal factors and foetal factors
maternal dystocia
inertia may be primary, in which case parturition does not commence, or may be secondary to some factor occuring during parturition
Maternal dystocia
divided into 2 categories
- insufficient straining
- obstruction of the birth canal
insufficient straining
most commonly the result of poor myometrial contractions, a condition that has been termed uterine inertia
Primary uterine inerta
rare in a cat
often seen with first time mums with small litters
or in older overweight bitches with large litters
foetal dystocia
foetal size
foetal presentation
maternal dystocia
hypocalcaemic causes may respond to the slow IV administration of calcium gluconate. Check HR as give ideally with ECG attached
the administration of the hormone oxytocin can be given as long as there is no obstructions to the birth canal
Maternal dystocia
Secondary uterine inertia
- the cessation of uterine contractions after they have started
- often following obstructive dystocia
obstruction of the birth canal
- may be result of abnormalities of the birth canal, such as skeletal or soft tissue deformities
Foetal Dystocia
Foetal size
- breed conformation
- actual foetal oversize- when the litter size is small or large foetuses develop within the uterus
- foetal abnormalities - such as anasarca pictured above. Foetal monsters
Foetal Dystocia
Abnormalities of foetal alignment
- variation from the normal presentation, position and posture of the foetus during delivery may result in dystocia
this may be corrected in certain cases by vaginal manipulation between contractions
Recognition of Dystocia
- straining for more than 1hr
- if allantochorion ruptured and no sign of puppy/kitten
-if contractions are strong but infrequent
- decline in temp but parturition hasn’t commenced in 24 hours
any purulent discharge
