Parturition

Question 1

stages of labor

Answer 1

**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

Question 2

in contraction,

myosin is ___

ATP is ____

Answer 2

myosin is phosphorylated

ATP is hydrolyzed

Question 3

actions of Progesterone in labor

Answer 3

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

Question 4

mechanism of premature ruprtre of membranes in preterm labor

Answer 4

apoptosis of cellular compontent of fetal membrane

matrix metalloproteinases play a role

Question 4

tx post-partum hemorrhage

Answer 4

uterine massage

xytocin

prostaglnadins

ergot alkaloid

Question 5

4 possible contributions to pre-term labor (categories only)

Answer 5

Uterine Distension

Meternal Fetal stress

Infection

premature rupture of membranes

Question 6

mechanism of maternal fetal stress in preterm labor

Answer 6

premature rise in cortisol and estrogens induce labor phenotpye and stmiulate fetal adrenal c19 hormones

Question 6

risk factors post-partum hemorrhage

Answer 6

preciptous labor OR prolonged

polyhydramnios
grand multiparity
large fetal weight
intrauterine infection
mutifetla gestation
retained placenta
uterine relaxation agents

Question 7

sheehan syndrome =

Answer 7

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

Question 8

window for pre-term labor

Answer 8

20-37wks

Question 10

CAP proteins =

examples (4)

Answer 10

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

Question 11

oxytocin increases ___ and ___ levels

Answer 11

prostaglandin and estrogen levels

Question 12

actions of estrogen in labor

Answer 12

increases gap junctions between myometrial cells

increases oxytocin receptor and prostaglandin receptor expression

Question 13

uterine changes in pregnancy

Answer 13

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

Question 14

possible triggers for labor cascade

Answer 14

fetal andrenal glands

increased maternal estrogens

increased prostaglnadins

increase in CAP

Question 15

cut offs for post-partum hemorrhage

Answer 15

500ml for vaginal loss

1000ml for cesarean loss

Question 16

process of uterine contractions

Answer 16

increae in intracellular Ca

Ca bind calmodulin

myosin light chain kinase activated

Question 16

mechanism of uterine distension to preterm labor

Answer 16

CAP expression

CRH and estrogen increase

oxytocin release

Uterine activation

Question 18

transition from quiescence phase to labor phase involves ____

Answer 18

shift from progesterone dominance to estrogen dominance

Question 20

identifiable risk factors for pre-term labor

Answer 20

Infection + peridontal dieae

low pre-pregnancy weight, SES, ethnicity

cervical shortening > decreased uterine space

Genetics (HX and FHx)

Smoking

Question 21

Rx to prevent preterm in patients with Hx or with shortened cerical length on ultrasound

Answer 21

progesterone

Question 22

therapies for preterm labor (stop contractions) that rely on preventign intracellualr Ca influx

Answer 22

Magnesium

Beta 2 adrenergic agonists

Ca channel blockers

prostaglandin synthesis inhibitors