Post-partum period Flashcards
Describe the post-partum period
Uterine involution (+ restoration of endometrium)
Elimination of bacterial contamination from repro tract
Resumption of ovarian function
Lactation/suckling
What is uterine involution?
Reduction in uterine size and involves:
- endometrial repair
- expulsion of lochia/foetal fluids
- restoring uterus so pregnancy can be re-established
Describe the cow anatomy 1 day post-partum
Cervix closing
large uterus
haemorrhaging on vaginal wall
Describe the cow anatomy 4 days post-partum
Shrinking uterus
lochia (foetal fluids) in vagina
cervix closed
What is the gravid horn?
The uterine horn which held the pregnancy
Describe cow anatomy 10 days post-partum
Follicular growth re-starting
Lochia disappeared
Heomarrhaging repaired
Describe the mechanism of uterus involution
Myometrial contractions:
- stimulated by oxytocin and PGF2a
- peristaltic waves towards cervix
- discharge of fluid/tissue debris
- compress vasculature
Co-ordinated atrophy:
- Myometrium stretch during pregnancy
- reduction in myometrial cell size
What stimulates oxytocin release post-partum?
Suckling
What is the effect of oxytocin post-partum?
milk production
myometrial contractions -> uterus involution
What is lochia?
Uterine discharge
‘second cleansing’
Remnants of foetal placenta and endometrial tissue
Odourless (bad odour = problem)
Blood-tinged
Describe the process of endometrial repair
Restoration of caruncle:
- necrosis => sloughing of placentome
- leaves caruncular stubs
Inter-caruncular endometrium:
- thins during pregnancy
- undergoes tissue remodelling post-partum
- new epithelial coverage
Why does uterine repair take longer in dairy cows?
Calves removed so no suckling => lower oxytocin levels
Why is uterine involution very quick in the mare?
Hastened by foal heat:
- comes into oestrus shortly after parturition
- release of oestradiol with heat aids involution
Small lochia
Little endometrial disruption
Normal by day 14
Why is uterine involution slow in the bitch?
2 lochia:
- 1st: from pigmented zone in placenta (green)
- 2nd: normal lochia, 4-6 weeks later
Endometrial repair:
- slow (3 months)
- multiple remodelling steps
Back to normal in 90 days
What normal processes aid the elimination of bacterial contamination during pregnancy?
Help eliminate by myometrial contraction
Phagocytosis by leukocytes (promoted by oestradiol/oestrus)
What conditions can pre-dispose the uterus to bacterial contamination in the peri- and post-partum period
Dystocia - human beings introducing bacteria, traumatic, cesarian etc.
Dead foetus
Dirty environment at parturition
Prolapse
Uterine inertia
Retained foetal membranes
Metabolic stress due to lactation
Describe the pathology of endometritis/’whites’
Persistent infection:
- reduced uterine defence mechanism
- devitalised tissue e.g., retained foetal membranes
Inflammation of endometrium
Opportunistic pathogens
Cause of infertility
Describe the cause of anoestrus during gestation
Prolonged, high progesterone:
- suppression of HPO axis
- folliclular waves but fewer and no ovulation (except in mares - endometrial cups)
- occasional oestrus behaviour
Describe the cause of anoestrus after parturition
Limited number of antral follicles
CL from pregnancy regressing
Period of low progesterone and low oestradiol
Limited -ve feedback
Describe the mechanism of ovarian rebound
Re-initiation of HPO axis:
- pituitary is refractory/unresponsive to GnRH
- FSH secretion initiated due to lack of -ve feedback
- antral follicular wave emerges
Resumption of ovarian activity:
- increasing sensitivity of gonadotropes to GnRH leads to:
- increased FSH stimulation of oestradiol production
- increased LH pulse frequency
- first ovulation (silent oestrus)
- short first oestrus cycle
Describe ovarian rebound in the sow
Profound suckling effects:
- early follicular activity
- but prolactin suppresses LH => no ovulation
Return to oestrus:
- weaning iniates oestrus and LH surge
Describe ovarian rebound in the dog
In late anoestrus:
- FSH high
- follicular waves re-appear (influenced by dopamine)
- enables synchrony of HPO axis
- enter follicular phase as wave of oestradiol suppresses FSH
Describe ovarian rebound in cats
Oestrus inhibited by lactation (not uniform)
Variable period of anoestrus post-weaning
Early weaning can cause early oestrus
What influences ovarian rebound?
Suckling (prolactin)
Milk yield/nutrition - decreasing body condition and negative energy balance delays rebound
Peri-parturient abnormalities - retained foetal membranes, endometritis
Seasonal - e.g., melatonin in the ewe
How can negative energy balance lead to ovarian pathologies
Describe abnormal ovarian rebound
Delayed onset of cyclicity
Cessation of ovarian activity
Ovarian pathologies:
- follicular/luteal cysts
- persistent CL
