Normal labor Flashcards
what does G TPAL stand for?
gravidity
parity (term, preterm, abortions, living)
definition: labor
increase in myometrial activity resulting in effacement and dilation of the uterine cervix
mean duration of human singleton pregnancy
280 days (40 wk) from first day of LMP
what is a term pregnancy?
period from 36 completed weeks (37.0) to 42.0 weeks
what is a preterm pregnancy?
onset of labor prior to 36 completed weeks
what is a postterm pregnancy?
continuing beyond 42 weeks
is labor diagnosed clinically or medically?
clinically
what are the criteria for labor diagnosis?
- regular painful contractions
- progressive cervical effacement and dilatation
- bloody show
phase 0 of labor
functional quiescence through inhibitors: progesterone, prostacyclin, relaxin
phase 1 of labor
cervical softening: slow progressive structural changes of ECM (collagen alterations)
phase 2 of labor
activation - myometrial changes, cervical ripening
phase 3 of labor
actual labor - three stages:
- oxytocin influence
- PGs, relaxin
- CRH
oxytocin really has its effect during which phase of labor?
phase 3
phase 4 of labor
- puerperium (postpartum interval)
- myometrium becomes rigid and in state of constant contraction - oxytocin influence
- uterine involution and cervical repair
what are the three mechanics of labor?
powers
passenger
passage
the ‘powers’ mechanics of labor are generated by what?
uterus
how is uterine activity described?
- frequency
- intensity
- duration
what is the classic definition of adequate uterine activity (how many contractions / minute)?
3-5 contractions in 10 minutes
definition: lie
spatial relationship of fetal spine to maternal spine
definition: presentation
fetal part that directly overlies the pelvic inlet
what does a compound presentation mean?
more than one fetal part directly overlies the pelvic inlet
what does malpresentation mean?
any presentation that is not cephalic with occiput leading
what is the best type of lie?
vertically oriented (longitudinal)
definition: fetal position
how is it described?
- relationship between a fetal denominator and the maternal pelvic
- described by 3 initials:
- 1st initial: fetal denominator
- 2nd and 3rd initial: maternal pelic quadrants toward which the fetal denominator points
(e.g. LOA, LOP)
what spot on the fetus marks the orientation?
posterior fontanelle (occiput)
definition: station
relationship of presenting part to maternal ischial spines
what does a “0” station mean? negative value?
head is at the ischial spines
negative value - above the spines
what is the name for the smallest part of the pelvic inlet?
true (obstetric) conjugate
what is the true (obstetric) conjugate?
smallest part of the pelvic inlet
what type of pelvic shapes is most conducive to labor?
gynecoid
what is the limiting factor for passage in the midcavity?
interspinous diameter
definition: stage 1 of labor
interval between onset of labor and full cervical dilation
what are the three subdivisions of stage 1 of labor?
- latent
- active
- descent
definition: latent phase of stage 1 labor
- between onset of labor and a point at which a change in slope of rate of cervical dilation is noted
- slow cervical change
definition: active phase of stage 1 labor
- greater rate of dilation
- most dilation
the most dilation, and greatest rate of dilation, occurs at what point of labor? at what cervical dilation value does it start?
active phase of stage 1 labor
4 cm
uterine contraction corresponds to what spinal levels?
T10 - L1
what is the most common complication of regional anesthesia?
hypotension
what are the durations of labor for nulliparous women? (total, 1st, 2nd, 3rd stages)
total: 10-26 hr
first: 10-24 hr
second: 30-120 min
third: 5-30 min
how do nulliparous labors compare with multiparous labors in terms of duration of stages?
30 minute 3rd stage
definition: stage 2 of labor
interval between full cervical dilation and delivery of infant
definition: stage 3 of labor
how long does this usually take?
- deliver of placenta
- less than 10 m (up to 30 m)
what are the changes in position of the fetal head during passage through the birth canal?
- engagement
- descent
- flexion
- internal rotation
- extension
- external rotation
- expulsion