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Flashcards in ch 13 Deck (50):

general flexion

-back rounded
-chin flexed to chest
-thighs flexed on abdomen
-arms crossed over thorax
-UC between arms and legs


deviated attitude

-can cause difficulty in labor
-cephalic presentation with head flexed in a way that exceeds limits of pelvis can lead to c/s, prolonged labor, vacuum, forceps


biparietal diameter

-9.25cm at term
-important indication of fetal size
-widest part of head entering pelvic inlet
-in complete flexion the diameter of head allows it to pass through canal



-reference point on the presenting part to the 4 quadrants of moms pelvis
-R or L
-A ,P, T
-presenting part (o,s,m,sc)


r or l

right or left side of mothers pelvis



anterior, posterior, or transverse location of presenting part in relation to the mothers pelvis


presenting part

-occiptial (O), sacral (S), chin or mentum (M), scapula (SC)
-determined by lie,attitude, extension or flexion of head



-relationship or presenting fetal part to an imaginary line drawn between the maternal ischial spines and is a measure of the degree of descent of presenting part through birth canal
-placement of present in part is measure by cm below ischial spine
- -5-+5
-should be determined when labor begins to determine rate of descent


station 0

presenting part is at level of the spines and station is ____


station -1

lower most portion of presenting part 1 cm above spines


station +4 and +5

birth is imminent


vertex presentation

-head is in complete flexion
-this position allows easy passage through true pelvis


sinciput presentation

-moderate extension
-diameter widens making passage difficult


brow presentation

-marked extension or deflection so largest diameter
-to large to permit head to enter pelvis is presenting


primary powers

-Ferguson reflex



-shortening and thinning of the cervix during the first stage of labor
-only thin edge of cervix can be palpated when this is complete
-degree is in % from 0-100



-the enlargement or widening of cervical opening and canal that occurs once labor has begun
-diameter or cervix increases from less than 1cm to 10cm
-occurs by strong contractions
-pressure on amniotic fluid while membranes are still intact or force on the presenting part can promote this
-scarring of cervix from infection or surgery can slow this


full dilation

-cervix is completely retracted and cant be palpated
-marks the end of the first stage of labor
-10 cm
-cranial bones over lap and membranes still intact


ferguson reflex

-in 1st and 2nd stage of labor increased intauterine pressure caused by contractions exerts pressure on the descending fetus and cervix
-when presenting part reaches perineal floor, mechanical stretching of cervix occurs
-stretch receptors cause release of oxytocin that triggers the maternal urge to bear down aka _______


uterine contractions

-independent of external forces
-may decrease in frequency and intensity temporarily if narcotics are given early in labor



-lengthen the first and second stages of labor
-slows the rate of fetal descent


secondary powers

-Bearing-down efforts
-has no effect on dilation
-important in the expulsion of infant from uterus and vagina after cervix is fully dilated


bearing down efforts

-woman uses these to aid in expulsion of fetus as she contracts diaphragm and abd muscles and pushes
-these efforts result in increased intraabdominal pressure that compresses the uterus on all sides and adds the powers of expulsive forces


complete efacement

-head is well applied to cervix


position of laboring woman

-Position affects woman’s anatomic and physiologic adaptations to labor
-Frequent changes in position:
Relieve fatigue
Increase comfort
Improve circulation
-Laboring woman should be encouraged to find positions most comfortable to her



-process of moving fetus, placenta, and membranes out of uterus and through birth canal
-Various changes take place in woman’s reproductive system in days and weeks before labor begins
-can be discussed in terms of mechanisms involved in process and stages woman moves through


signs preceding labor

-Lightening or dropping
-Bloody show



-in first time preg uterus sinks down and forward about 2wks before term when presenting part (usually head) descends into true pelvis
-this settling happens gradually
-after this woman feel and less congested and breather easier
-usually more bladder pressure results and there is a return of urinary frequency
-in multiparous it may not take place until contractions are established and true labor is in progress


bloody show

-profuse vaginal mucous in response to congestion of vag mucous membranes
-brown or blood tinged mucous may be passed
-cervix become soft (ripe) and partially effaced and may begin to dilate
-membranes may rupture spontaneously


onset of labor

-true labor cannot be ascribed to single cause.
-Many factors involved, including changes in maternal uterus, cervix, and pituitary gland
-hormones produced by fetus may contribute
-uterine distension and pressure seem to be associated
-decreased progesterone and increased estrogen, oxytocin, prostaglandins
-these coordinated effects of these factors result in the occurrence of strong, regular, rhythmic contractions
-outcome of working these factors working together is the birth and expulsion of fetus


stages of labor



first stage

-early aka latent (also in second stage)
-active (also in second stage)
-last from the onset of regular contractions to full dilation of cervix
-onset is difficult to establish and is an estimate


early labor

0-4 cms
-more progress in effacement of cervix
-little increase in descent
-fetus descends passively through canal rotating to an anterior position resulting from contractions
-urge to bear down is weak and some woman dont experience it at all


active labor

4-7 cms
-woman has a strong urge to bear down and push
-presenting part of the fetus descends and presses on the stretch receptors of the pelvic floor



7-10 cms


second stage of labor

-Average 1-3 hours first baby
-Usually shorter second and subsequent babies
-last from the time the cervix is fully dilated to the birth of fetus


third stage of labor

-last from the birth of fetus until placenta is delivered
-placenta separates with the 3rd or 4th strong contraction after the infant has been born
-after separation the placenta can be delivered wit the next contraction


fourth stage of labor

-last 2 hrs after delivery of placenta
-period of immediate recovery
-homeostasis is reestablished
-parent-child bonding and attachment begins
-breast feeding is initiated
-important period for observation of complications such as hemorrhage


surge of energy

A pregnant woman is at 38 weeks of gestation. She wants to know if any signs indicate that “labor is getting closer to starting.” The nurse informs the woman that this is a sign that labor may begin soon:


cardinal movements of labor

-position of fetal head seen by birth attendant
-Internal rotation
-Restitution and external rotation
-Expulsion (birth)


mechanisms of labor

-the turns and adjustments necessary in the human birth processes
-for vag birth to occur the fetus must adapt to birth canal during descent



-when the biparietal diameter of the head passes the pelvic inlet


fetal adaptation

-Fetal heart rate
-Fetal circulation
-Fetal respiration
-Other behaviors


maternal adaptation

-Cardiovascular changes
-Respiratory changes
-Renal changes
-Integumentary changes
-Musculoskeletal changes
-Neurologic changes
-Gastrointestinal changes
-Endocrine changes



-provides reliable and predictive info about condition of fetal O2
-at term 140
-normal range 110-160
-higher at 20wks (160)
-decreases as fetus reaches term
-accelerations and decelerations can be expected in response to sponatenous fetal movement, vag exam, fundal pressure, contractions, abd palpation, and fetal head compression


fetal circulation

-can be affected by maternal position, contractions, BP, and UC blood flow
-contractions during labor decrease circulation
-fetus adapts to contractions and are able to compensate
-UC moves freely in AF fluid but it can be compressed during contractions


fetal rr

-chemoreceptors in aorta and carotid prepare fetus for initiating respiration immediately after birth
-lung fluid is cleared from air passages as baby moves through canal during labor and birth
-oxygen pressure (Po2), ph, bicarb, and resp movement decreases during labor
-Pco2 increases


mom co

-by end of first stage of labor, during contractions it increases
-peaks 310-30 mins after vag and c/s birth and returns to prelabor baseline in first pp hour
-drop in HR accompanies this increase


mom bp

-increase during contractions and return to baseline between contractions
-top number increases more than bottom
-laboring woman is at greater risk for supine hypotension


mom rr

-increased with increased physical activity and greater o2 consumption
-resp alk, hypoxia, and low co2
-o2 consumption in second stage unmedicated woman doubles
-anxiety also increases o2 consumption