Parturition Flashcards
Phase 1
Characterized by presence of
Contractile protein
Low intensity myometrial contractions felt during quiescent phase, do not normally cause cervical dilatation.
Braxton hicks contraction or false labor
Characterized by increase in tissue compliance, yet the cervix remains firm and unyielding.
Cervical softening
Cervix is closed and firm like nasal cartilage
Non pregnant woman
At the end of pregnancy, the cervix is easily distensible and the consistency is similar to the lips of the oral cavity
Pregnant woman
Cervical shortening between what weeks has been associated with increased case of preterm delivery
16-24 weeks
Softening results from
Increased vascularity Stroma hypertrophy Glandular hypertrophy Hyperplasia Structural changes of ECM
Softening is preceded by
Increase in collagen solubility
The one that being assembled to collagen fibers
Collagen fibrils
Phase 2
Preparation for labor
Cervical ripening
To prepare for labor, the myometrial tranquility of phase 1 must be suspended
Uterine awakening and activation
Phase 2 occurs during the last _______ weeks of pregnancy! this prepare the uterus for labor contraction
6-8
Myometrial changes
Results from alterations in the expression of key proteins that control contractility, what proteins?
Oxytocin receptor
Prostaglandin F receptor
Connexin 43
Myometrial changes
Myometrial oxytocin receptors markedly increase along with
Connexin 43
Myometrial changes
Agents that stimulate contractions
Uterotonins
Formation of lower uterine segment from isthmus. Fetal head often descends to or even through the pelvic inlet.
Lightening
The abdomen also undergoes a change in shape described often as
The baby dropped
Cervical ripening during phase 2
Before contractions begin, the cervix must undergo
Extensive remodeling
10-15% smooth muscle cells and the others are connective tissues namely
Collagen
GAGs
Proteoglycans
Elastin
Responsible for structural deposition of the cervix
Contains 3 alpha chains
Changes in collagen regulate
Remodeling
Collagen
High molecular weights polysaccharides that complex with proteins and proteoglycans
PP
GAGs
Glycoproteins that contain a protein core and GAG chains
PG
Proteoglycans
At least three small leucine-rich proteoglycans are expressed in the cervix
Decorin
Biglycan
Fibromodulin
Inflammatory changes
Marked changes within the ECM during ripening accompanied by
Stromal invasion with inflammatory cells
Inflammatory changes
Cervical chemoattractant then
Inflammatory cells then
Release proteases then
Degradation of collagen
Treatment to induce cervical ripening
Prostaglandin E2/F2
For labor induction
Collagen
GAG
Phase 3
Labor
Phase 3 labor
Uterine contraction
Cervical dilatation
Expulsion of both fetus and placenta
Stage 1
Clinical onset of labor
Stage 1 begins and end?
Begins- spaced uterine contraction of sufficient frequency, intensity and duration.
- cervical thinning or effacement
Ends- when the cervix is fully dilated 10cm
Extrusion of the mucus plug that had previously filled the cervical canal during pregnancy.
Bloody show
Stage 1 there’s also presence of distinct upper and lower uterine segments
Change in the shape of the uterus.
Uterine contraction painful due to
Hypoxia
Compression of nerve ganglia
Cervical stretching
Stretching of the peritoneum overlying the fundus
Mechanical stretching of the cervix enhances uterine activity. Maybe due to the release of oxytocin has been suggested but not proven.
Ferguson reflex
Manipulation of the cervix and “stripping” the fetal membrane is associated with an increase in blood levels of
Prostaglandin F2 metabolite
Interval between contractions, diminishes gradually from
10 to 1minute or less in the second stage
Compromise utero placental BF sufficiency to cause fetal Hypoxemia
Unremitting contraction
Active phase labor
30-90 sec
Average of 1 minute
Amniotic fluid pressure
20-60 mmHg
Phase 1
Uterine quiescence and cervical softening
