Parturition Flashcards
stages of labor
**1. **latent - contraction with with slow cervical dilation
**1. **Active: contractionswith fast dilation
**2. **complete dilation until delivery
**3. **post delivery of fetus until placenta
4.one hour post-placenta. Constant myometrial contraction that limtis blood loss
in contraction,
myosin is ___
ATP is ____
myosin is phosphorylated
ATP is hydrolyzed
actions of Progesterone in labor
inhbits intracellular Ca entry
inhibits relese from SR
membrane hyperpol via K channels
inhibits expression of contraction associated protein genes
levels are contant before and during labor
mechanism of premature ruprtre of membranes in preterm labor
apoptosis of cellular compontent of fetal membrane
matrix metalloproteinases play a role
tx post-partum hemorrhage
uterine massage
xytocin
prostaglnadins
ergot alkaloid
4 possible contributions to pre-term labor (categories only)
Uterine Distension
Meternal Fetal stress
Infection
premature rupture of membranes
mechanism of maternal fetal stress in preterm labor
premature rise in cortisol and estrogens induce labor phenotpye and stmiulate fetal adrenal c19 hormones
risk factors post-partum hemorrhage
preciptous labor OR prolonged
polyhydramnios
grand multiparity
large fetal weight
intrauterine infection
mutifetla gestation
retained placenta
uterine relaxation agents
sheehan syndrome =
hypovolemia from obsterical lood loss leads to pituiray infarct or necrosis
lacation failure
hypoglycemia
life thretening hypotension from adrenal insufficiency
Possible lag time for symptom onset
window for pre-term labor
20-37wks
CAP proteins =
examples (4)
uterine stretch and estrogen upregulate proteins that initiate excitation and incresae frequency and amplittude of contractions
Gap junction protein connexin 43
Corticotropin releaseing hormone receprotr
oxytocin receptor
COX2
oxytocin increases ___ and ___ levels
prostaglandin and estrogen levels
actions of estrogen in labor
increases gap junctions between myometrial cells
increases oxytocin receptor and prostaglandin receptor expression
uterine changes in pregnancy
increase in size (4-70g to 1200 grams
myometrial cells prolif early
myometiral cells hpertrophy in later half
gap junction sbetween myometrial cells increase
major increase in blood supply
possible triggers for labor cascade
fetal andrenal glands
increased maternal estrogens
increased prostaglnadins
increase in CAP
cut offs for post-partum hemorrhage
500ml for vaginal loss
1000ml for cesarean loss
process of uterine contractions
increae in intracellular Ca
Ca bind calmodulin
myosin light chain kinase activated
mechanism of uterine distension to preterm labor
CAP expression
CRH and estrogen increase
oxytocin release
Uterine activation
transition from quiescence phase to labor phase involves ____
shift from progesterone dominance to estrogen dominance
identifiable risk factors for pre-term labor
Infection + peridontal dieae
low pre-pregnancy weight, SES, ethnicity
cervical shortening > decreased uterine space
Genetics (HX and FHx)
Smoking
Rx to prevent preterm in patients with Hx or with shortened cerical length on ultrasound
progesterone
therapies for preterm labor (stop contractions) that rely on preventign intracellualr Ca influx
Magnesium
Beta 2 adrenergic agonists
Ca channel blockers
prostaglandin synthesis inhibitors
