Parturition

Question 1

progesterone

Answer 1

progesterone block and uterine quiescence
cervical closure
luteal and placental sources

Question 2

estrogens

Answer 2

produced during pregnancy, can silence estrogen

Question 3

progesterone profiles

Answer 3

fall at parturition- bitch, queen, sow

some peak towards parturition prior to rapid decline= woman, mare, cow and ewe

Question 4

woman endocrine profile

Answer 4

E2 and P4 run together and rapid decline as hit parturition

Question 5

Ewe endocrine profile

Answer 5

P4= gradual rise throughout and fall at parturition

E2 peaks right before parturition and falls at parturition

Question 6

Sow endocrine profile

Answer 6

At ovulation= peak of P4

E2 peaks as approaches parturition

Question 7

Mare endocrine profile

Answer 7

P4= birise and declines as estrogen increases prior to estrogen decline at parturition

Question 8

Cow endocrine profile

Answer 8

P4 high at ovulation and then decreases, remains steady throughout before a steady incline and drop at parturition
estrogen has an increase prior to parturition

Question 9

progesterone

Answer 9

pro gestational

Question 10

estrogen

Answer 10

increased uterine responsiveness

Question 11

PGF2a

Answer 11

luteolysis and contractions

Question 12

oxytocin

Answer 12

contractions

Question 13

relaxin

Answer 13

genital tract softening

Question 14

parturition concept

Answer 14

must be timed to match degree of fetal maturation with the ability of the fetus to survive outside the uterus

once initiated the process of parturition is difficult to interrupt or delay

Question 15

the liggins contribution

Answer 15

fetuses control parturition timing

hypophysectomy= pituitary gland removal or adrenalectomy prevents parturition

infusion of ACTH or cortisol induces premature parturition and visceral maturation

women with preterm labor treated with glucocorticoid

Question 16

critical observation in experiments

Answer 16

fetal sheep exposed to agent have a malformation that is characterized by delay in parturition

Question 17

Fetal Hypothalamic-pituitary-adrenal (HPA) axis

Answer 17

activation/maturation of the fetal HPA axis results in increase in fetal corticotropin releasing hormone (CRF/CRH), ACTH and cortisol

fetal stress= hypoxia, overcrowding, nutritional concern

Question 18

Fetal HPA

Answer 18

hypothalamus (CRF) to ant. pituitary (ACTH) to adrenal cortex (cortisol)

Question 19

fetal cortisol

Answer 19

induces enzymatic changes in placenta, communicates with the dam

promotes prostaglandin synthesis

instrumental in fetal maturation (ex:lungs)

fetal cortisol released= useful because causes lung to mature so have surfactant

Question 20

Sheep

Answer 20

decrease progesterone and increase estrogen which causes more irritation, gravid uterus and cervix softening

Question 21

enzymatic pathway

Answer 21

fetal cortisol induces

progesterone to estradiol via enzymatic conversion in the placenta

progesterone falls and estrogen rises

aromatase changes by taking away number of carbons

Question 22

progesterone falls

Answer 22

1. enzymatic- fetal cortisol induces placental conversion of progesterone to estrogen
2. luteolysis- PGF2a, importance in CL dependent species

removal of progesterone block

Question 23

estrogen rises

Answer 23

because progesterone decline

enzymatic- fetal cortisol induces placental conversion of progesterone to estrogen

increases uterine sensitivity to oxytocin, increased lubrication and softening, promotes release of PGF2a

Question 24

relaxin

Answer 24

encourages pelvic, genital tract and cervical softening to facilitate parturition

externally assessed as parturition nears: vulva, perineum and pelvic ligaments soften and relax

Question 25

prostaglandin

Answer 25

PGF2a release will cause luteolysis if the CL still present PGF2a will cause uterine (myometrial) contractions- smooth m.

Question 26

oxytocin

Answer 26

will cause myometrial contractions very high at parturition uterine contractions can subsequently promote more oxytocin and PGF2a release Ferguson reflex

Question 27

Ferguson reflex

Answer 27

``` neuroendocrine reflex dissension of the cervix and vagina causes release of oxytocin from the posterior pituitary uterine contractions result further dissension occurs more oxytocin released- lots of feedback ```

Question 28

process triggered by fetal stress

Answer 28

increase in fetal ACTH, fetal cortisol released

Question 29

Fetal cortisol

Answer 29

increases PGF2a release- triggering relaxin (pelvic ligament stretching) and luteolysis along with increased myometrial contractions can trigger enzymes that convert P4 to E2 which causes increased myometrial contractions and increased secretion by female tract allowing lubrication

Question 30

increased myometrial contractions

Answer 30

increase pressure, increase cervical stimulation, increase oxytocin, maximum pressure

Question 31

Thorburn hypothesis

Answer 31

prostaglandin E2 injections into fetuses IV increases ACTH secretion PGE2 secreted from ovine placenta= hormonal signal which stimulates fetal ACTH secretion at the end of gestation

Question 32

PGF2a vs. PGE2

Answer 32

OH vs. double bond O

Question 33

3 stages of parturition

Answer 33

preparation, fetal expulsion with true labor, expulsion of the fetal membranes

Question 34

Stage I

Answer 34

preparation cervical dilation, myometrial contractions, some fetal positioning

Question 35

Stage II

Answer 35

fetal expulsion with true labor myometrial and abdominal contractions (generally obvious)

Question 36

Stage III

Answer 36

expulsion of the fetal membranes

Question 37

species variability in length of each stage

Answer 37

Bovine- cow= slow, Heifer= even slower | horse= fast explosive

Question 38

forceful contractions

Answer 38

uterine myometrial (smooth m.) contractions abdominal contractions calcium necessary

Question 39

Horse stage I

Answer 39

preparation relaxed tail head, soft perineal tissues, sweating, colicky, nervous

Question 40

Stage II horse

Answer 40

begins with chorioallantois rupture, explosive in mare water breaks, amnion visible and fetal expulsion completed

Question 41

stage III horse

Answer 41

placental expulsion

Question 42

bovine parturition

Answer 42

stage I= preparation isolated from herd, udder= colostrum and edema, tissue softening

Question 43

Stage III in cows

Answer 43

mechanism of fetal membrane passage continued myometrial contractions vasoconstriction and inflammation problem if retain fetal membranes

Question 44

Puerperium

Answer 44

time from fetal delivery until complete uterine involution involution varies by species: cow-about month to 1.5 months mare- about 2 weeks bitch- about 2 months and more

Question 45

Uterine involution

Answer 45

gross appearance of uterus- dramatic decrease in uterine size, fetal membrane expulsion, evacuation of fluids remaining in uterus histological appearance of uterus= tissue healing clearance of bacterial contamination from act of parturition

Question 46

Lochia

Answer 46

normal postpartum debris and fluids which are passed out through the vagina and vulva length of time of discharge varies among species minimal odor

Question 47

clinical relevance

Answer 47

assisted delivery for dystocia | therapy for retention of fetal membranes

Question 48

general parturition

Answer 48

Fetal HPA activation, decreased progesterone, increased estrogen, increased oxytocin and PGF2a, relative uterine quiescence changes to dramatic uterine activation