ch 16. labor & birth process Flashcards
The 5 P’s of pregnancy (5)
passageway (pelvis)
passenger (fetus): relationship of maternal pelvis -> presenting part
power: physiologic forces of labor
positioning (of mother)
psychosocial considerations
birth passageway (what (3), soft tissues of (3), types (4)
1) true pelvis
- inlet
- midpelvis (pelvic cavity)
- outlet
2) soft tissues of cervix, vagina, pelvic floor
3) types of pelvises:
- gynecoid
- android
- anthropoid
- platypelloid
TIP:
+4 out the door
inlet is also know as
linea terminalis
gynecoid (2)
inlet ROUNDED with all inlet diameters adequate midpelvis diameters adequate with parallel side walls
- outlet adequate
implications: favorable for vaginal birth
android (3, implications (3))
inlet HEART SHAPED with short posterior sagittal diameter
- midpelvis diameter reduced
- outlet capacity reduced
implications:
- NOT favorable for vaginal birth
- descent into pelvis slow
- fetal head enters pelvis in transverse or posterior position with arrest of labor frequent
anthropoid (3, implications (1))
inlet OVAL in shape, with long anterioposterior diameter
- midpelvis diameters adequate
- outlet adequate
implications:
- favorable for vaginal birth
platypelloid (3, implications (3))
inlet OVAL in shape, with long transverse diameters
- midpelvis diameters reduced
- outlet capacity inadequate
implications:
- fetal head engages in transverse position
- difficult descent through midpelvis
- frequent delay of progress at outlet of pelvis
birth passenger (fetus) (4)
- head
- attitude
- lie
- presentation
fetal head (2, key landmarks (4))
1) fetal skull
2) sutures: fontanelles (presentation determination)
3) key landmarks:
- mentum: fetal chin
- sinciput: anterior area known as the brow (brow -> anterior font.)
- vertex: area between anterior and posterior fontanelles (how baby presents)
- occiput: area of fetal skull occupied by the occipital bone, beneath the posterior fontanelle
fetal attitude (3)
- relation of the fetal body parts to one another
- normal attitude: general flexion
- deviations contribute to longer, more difficult labor -> causes fetus to present larger diameters to the fetal head to the maternal pelvis
fetal lie (3)
- relationship of the long, or cephalocaudal, axis (spinal column) of the fetus to the long, or cephalocaudal, axis of the mother
- longtitudinal lie: cephalocaudal axis of fetal spine is parallel to the mother’s spine (99.5% all births)
- transverse lie: cephalocaudal axis of fetal spine is at a right angle to the mother’s spine (shoulder presentation, cradle in mom’s pelvis)
fetal lie complete breeched (attitude, presenting part, landmark)
- attitude: flexed hips/knees
- presenting part: buttocks
- landmark: sacrum
fetal lie frank breeched (attitude, presenting part, landmark)
- attitude: flexed hips, extended knees with legs against abdomen and chest
- presenting part: buttocks
- landmark: sacrum
fetal lie footling: single, double (attitude, presenting part, landmark)
- attitude: extended hips and atleast one knee extended with foot in cervical canal
- presenting part: buttocks
- landmark: sacrum
fetal lie kneeling: single, double (attitude, presenting part, landmark)
- attitude: extended hips, flexed knees
- presenting part: feet (one or two)
- landmark: sacrum
cephalic fetal presentation (4)
- vertex: when presenting part is the occiput
- sinciput: fetal head is partially flexed
- brow presentation: fetal head is partially extended
- face: fetal head is hyperextended
breech fetal presentation (3)
- complete: knees and hips flexed, thighs are on the abdomen, calves are on the posterior aspect of the thighs
- flank: hips flexed, knees extended
- footling: hips and legs are extended
relationship of maternal pelvis and presenting part (2 + fetal position (3)
1) engagement: presenting part thru pelvis inlet
2) station: ischial spines
3) fetal position (3 notations):
- right (R) or left (L) side of maternal pelvis
- landmark of fetal presenting part: occiput (O), mentum (M), sacrum (S), or acromion process (A)
- anterior (A), posterior (P), or tranverse (T), depending on whether the landmark is in the front, back, or side of the pelvis
TIP:
Right/Left occiput anterior (easiest)
physiologic forces of labor: power (uterine contractions (7)
1) uterine contractions
- increment (mmuscle contracts and tightens)
- acme (peak contraction)
- decrement (release)
- frequency (begin of one contraction to begin of next)
- duration (begin at end of one contraction)
- intensity
- resting tone (need to have rest in between contraction)
psychosocial considerations (6)
- readiness of birth and motherhood
- fears
- anxieties
- birth fantasies
- level of social support
- perception of birth experience may influence mothering behaviors
positive birth experiences (12)
- motivation for the pregnancy
- attendance at childbirth education classes
- a sense of competence or mastery
- self confidence and self esteem
- positive relationship with mate
- maintaining control during labor
- support from mate or other person during labor
- not being left alone in labor
- trust in the medical/nursing staff
- having personal control of breathing patterns, comfort measures
- choosing a physician/certified nurse midwife who has a similar philosophy of care
- receiving clear information regarding procedures
physiology of labor (3 hypothesis)
1) progesterone withdrawal hypothesis
- progesterone produed by the placenta relaxes uterine smooth muscle
- decrease in availability of progesterone to myometrial cells
- yet unknown antiprogestin
2) prostaglandins hypothesis
- prostaglandins known to induce labor? not sure why?
3) corticotropin releasing hormone hypothesis
- known to stimulate synthesis of prostaglandins
TIPS:
- progesterone maintains pregnancy
- decrease in progesterone allows for contractions to occur
myometrial activity (2)
1) effacement (before dilatation)
- taking up of the internal os and the cervical canal into the uterine side walls
- thinning and shortening (pullback) of the cervix that occurs late in pregnancy or during labor (0-100%)
2) cervical dilatation
- process in which the cervical os and the cervical canal widen from less than 1 cm to approximately 10 cm, allowing the birth of the fetus
dilation examples
1cm: cherrio
2cm: penny
3cm: banana
4cm: ritz cracler
5cm: babybel
6cm: cookie
7cm: can of pop
8cm: baseball
9cm: doughnut
10cm: bagel
musculature changes in the pelvic floor (3)
- muscles in the pelvic floor draw the rectum and vagina upward and forward during each contraction
- pressure of fetal head thins out perineal structure from 5cm -> 1cm
- normal physiologic anesthesia is produced due to decreased blood supple to area
premonitory signs of labor (7)
- lightening “baby drops”
- braxton hicks contractions
- cervical changes
- blood show: pink tinged mucous plug (release)
- rupture (release) of membranes
- sudden burst of energy (nesting, overcleaning)
- weight loss, N/V/D, indigestion
true labor (7) vs. warm up contractions (6)
1) true labor:
- contractions at regular intervals
- intervals between contractions gradually shorten
- contractions increase in duration and intensity
- discomfort begins in back and radiates around to abdomen
- intensity usually increases with walking (no effect on false labor)
- cervical dilatation and effacement are progressive
- contractions do NOT decrease with rest or warm tub bath
2) false labor:
- contractions are irregular
- usually no change in contractions
- discomfort usually in abdomen
- walking has no effect on or lessens contractions
- no change in dilatation or effacement
- rest and warm tub baths lessen contractions
stages of labor (4)
1) first stage: latent, active, transition (0-10cm)
2) second stage: resting, active (10cm - birth)
3) third stage: birth baby -> placenta (5-30 min)
- after birth of infant, uterus contacts firmly, decreased surface area of placental attachment
- placenta begins to separate: bleeding, membranes last to separate
- placental birth: shiny shultz (fetal side), dirty duncan (maternal side)
4) fourth stage: 1st hour after birth
- 1-4 hours after birth
- blood loss 250-500 mL vaginal birth
- uterus remains contracted
- mother is starving
- shaking chill (neurological response)
- hypotonic bladder (decreased tone + neural sensation)
TIPS:
first labor: lasts 16-18 hours
labor after that cuts in half
caesarean birth: loss 1 L blood, greater than 1L = hemorrhage
signs of placental separation (4)
- globular shaped uterus
- rise of fundus of uterus in abdomen
- sudden gush of trickle of blood
- further protrusion of the umbilical cord out of the vagina
maternal systemic response to labor (7)
1) cardiovascular: stressed by contacrtions and pain, anxiety
2) blood pressure: increases during contractions
3) fluid and electrolyte balance: diaphoresis
4) respiratory system: increased oxygen demand
5) renal system: polyuria
6) GI system: prolonged gastric emptying time
7) immune systemL increased WBC during labor -> 25,000/mm3 - 30,000/mm3
fetal response to labor (5)
1) heart rate changes: early decelerations
2) acid base balance in labor: blood flow to fetus slowed during acme of contractions, can lead to slow decrease in fetal pH
3) hemodynamic changes: fetal BP protective mechanisms,
4) behavioral states: sleep and awake
5) fetal sensation: fetus experiences labor (pain, sleep-wake states, as early as 6 months, skin to skin contact can help with pain/comfort)
