Labor & Delivery L4 Flashcards
How many stages of labor are there?
4
describe stage 1 of labor
0-10cm dilation and 0-100% effacement or ~4cm thick to <0.5cm thick
phase 1 = onset of regular, strong contractions that change the cervix to full dilation of cervix and full effacement
has latent and active phases
how long does stage 1 labor last?
several hours to several days
describe stage 2 of labor
10cm dilation and 100%/<0.5cm effacement - birth of fetus
has latent and active phases
how long does stage 2 of labor last?
several minutes to 4-5 hours
what are the latent and active phases of stage 1 labor?
latent: 0-5cm dilation
active: 6-10cm dilation
what are the latent and active phases of stage 2 labor?
latent: passive descent of fetus (laboring down)
active: pushing with contractions
describe stage 3 of labor
birth of fetus to birth of placenta
oxytocin bolus started as soon as baby delivers
how long does stage 3 labor take?
5-30 minutes
describe the oxytocin bolus administered in stage 3 following delivery of baby
20-30 units in 500-1000mL
or
10 U IM
describe stage 4 of labor
expulsion of placenta to the stabilization of pt
how long is stage 4 labor?
~ 1 hour post birth (recovery is usually about 2 hours)
what are the 5 Ps that affect the process of labor and birth?
- passenger
- passageway
- powers
- position (of birthing person)
- psychological response
what is fetal presentation?
the fetal part entering the pelvis first
what are the fetal presentations?
1) cephalic (head first) - 96%
2) breech (butt first) - 3%
3) transverse (shoulder first) - 1%
what are factors that influence presentation?
1) fetal lie
2) fetal attitude
3) extension/flexion of the fetal head
fetal lie
long axis of the fetus in relation to the long axis of mother
(vertical/longitudinal or transverse/horizontal)
fetal attitude
relation of the fetal body parts to one another (usually general flexion)
extension/flexion of the fetal head
flexed to chest or extended
changes biparietal diameter
biparietal diameter
the largest transverse diameter of the head. its an important indicator of fetal head size
how is fetal presentation diagnosed?
1) leopold’s maneuvers
2) verify with ultrasound
Fetal position & station
relationship between presenting part and (occiput most often) and the maternal pelvis (4 quadrants)
station
presenting part in relation to the ischial spines (-5cm - +5cm)
engagement
occurs when biparietal diameter (typically) passes through pelvic brim (usually around 0 station)
0 station
fetal lie
how the axis of the fetal spine lines up with mothers
* longitudinal or vertical - spines run in the same direction
* transverse or oblique - the spines crisscross
what is the external way to rotate a fetus?
- ultrasounds verifies position
- MD performs the attempt to rotate fetus
- meds may be used to relax the uterus
vertex presentation
neck fully flexed (chin tucked) - needs minimal passageway clearance
sinciput presentation
neutral neck flexion/extension - needs moderately sized passageway
brow presentation
neck fully extended (chin up) - needs the significantly more passageway clearance than the others
when does the placenta start forming?
at implantation
what are the membranes that form the placenta?
- decidua basalis
- chorion
cotyledons
the functional units of the placenta (10-15/placenta)
how quickly is the placenta fully formed?
completed by 12 weeks
what happens if there is a break in the placental membrane?
it allows mixing of maternal and fetal blood (Rh sensitization)
the placenta is a ______ gland
endocrine
what hormones does the placenta produce for pregnancy?
1) hCG - human chorionic gonadotropin
2) hPL - human placental lactogen
3) estrogen (estriol
4) progesterone
what hormone does a pregnancy test detect?
hCG - human chorionic gonadotropin
what effect does hPL (human placental lactogen) have?
1) similar to growth hormone
2) increases resistance to insulin and facilitates glucose transfer across membrane
what effect does placenta produced estrogen have?
stimulates uterine growth
what effects do placenta produced progesterone have?
1) maintains endometrium
2) decreases contractility of uterus
what are the metabolic functions of the placenta?
1) respiration
2) nutrition
3) excretion
4) storage
factors that can affect the functions of the placenta:
1) smoking
2) drug use
3) poor nutrition
4) increased BP
5) maternal positions
6) infection
7) trauma
what can happen in the placenta is retained after delivery of the fetus??
1) can lengthen the 3rd stage of labor and lead to surgical removal
2) increases the risk of PPH (postpartum hemorrhage)
PPH
postpartum hemorrhage
which placentas may have calcifications?
older placentas can have calcifications which can affect oxygenation
what type of decel will this cause?
variable decels
passageway includes both…
- body pelvis
- soft tissues
what parts of the bony pelvis affect the passagway?
1) ilium
2) ischium
3) pubis
4) sacral bones
5) shape
shapes of the pelvis:
1) gynecoid - rounded with less pronounced ischial spines
2) android - heart shaped with a longer sacrum
3) anthropoid - oval shaped, wider anteroposterior diameter
4) plapetelloid - flat anterior and posterior (transverse oval shape)
what is the most common and least common pelvic shapes?
gynecoid is most common, plapetelloid is least common
list the soft tissue of the passageway
1) lower uterine segment
2) cervix
3) pelvic floor muscles
4) vagina/introitus
powers of labor
1) primary powers
2) secondary powers
primary powers
involuntary uterine contractions:
* contraction starts at the fundus and works its way down in waves
* assessed via monitor or palpations of fundus
what are the primary responsibilities of primary powers?
responsible for dilation of the cervix and fetal decent
effacement
thinning of the cervix
* cervix usually 3-4cm long x 1cm thick
* effacement expressed in % or cm long
what are the three phases of uterine contraction?
1) increment
2) acme
3) decrement
how is contraction frequency measured?
beginning of one u/c to the beginning of the next
how is regularity of contractions classified?
either regular or irregular
how is duration of a contraction measured?
beginning of a u/c to the end of contraction
how is contraction strength classified?
mild, moderate, or strong
IUPC
measures strength of U/Cs with a resting tone usually 15-20 mmHg
Ferguson’s reflex
primary power:
1) presenting fetal part reaches thee perineal floor which causes the cervix to stretch
2) stretch receptors in the vagina trigger exogenous oxytocin release which triggers a maternal urge to bear down
secondary powers
bearing down efforts by the woman once cervix has dilated to 10cm
* increases intraabdominal pressure on the uterus which helps to expel fetus
* for best results, wait for maternal urge to bear down
what can prolonged pushing effort cause?
it can lead to fetal hypoxia/acidosis and severe maternal perineal lacerations
physiologic birth positions:
1) lithotomy
2) hands and knees
3) standing
4) side-lying
5) semi-fowlers
6) squatting
7) knees together
factors influencing a woman’s reaction to physical/emotional crisis of labor:
1) self-confidence
2) partner/support person relationship
3) feeling in control and empowered
4) support during delivery
5) not being left alone
6) trust in the healthcare team
7) pain management
8) length of labor
what can increased length of labor process cause?
can lead to:
* exhaustion
* increased anxiety
* increased risk of medical interventions
what are factors that are associated with improved birth experience?
1) motivation for pregnancy
2) attendance to childbirth classes
3) sense of competency/mastery
signs preceding labor:
1) lightening
2) return of urinary frequency
3) backache
4) stronger braxton hicks contractions
5) weight loss of 0.5-1.5kg
6) surge of energy
7) increased vaginal discharge or bloody show
8) cervical ripening
9) possible rupture of membranes
what is it called when ROM occurs before labor?
pre-labor rupture of membranes (PROM)
Cardinal Movements of Labor
engagement
baby engaged in the true pelvis
* when the biparietal diameter of the head passes the pelvic inlet, the head is engaged in the pelvic inlet
acynclitism
head cocked - makes descent during engagement more difficult and can lead to CPD (cephalopelvic disproportion)
Cardinal Movements of Labor
descent
it depends on at least four forces:
1) pressure exerted by the amniotic fluid
2) pressure exerted by the fundus contracting on the fetus
3) pressure from contraction of the maternal diaphragm and abdominal muscles in second stage of labor
4) extension and straightening of the fetal body
Cardinal Movements of Labor
flexion
occurs when presenting part hits soft tissue (cervix, pelvic wall, pelvic floor) fetus flexes chin to chest
Cardinal Movements of Labor
internal rotation
the mothers pelvis is widest in the transverse diameter so the baby’s head must rotate for it to exit.
* rotation begins at the level of the ischial spines and completes when the presenting part reaches the lower pelvis
Cardinal Movements of Labor
extension
the baby’s head emerges via extension. occiput, then face, then chin
Cardinal Movements of Labor
reinstitution
once the head emerges, it rotates 45 degrees to the position it was in before internal rotation while it was passing through the pelvis aligning the head back up with the shoulders and back
Cardinal Movements of Labor
external rotation
after reinstitution, the head rotates further as it aligns with the shoulders that are rotating to make it through the pelvis just as the head did
Cardinal Movements of Labor
expulsion
after the birth of the shoulders, the head and shoulders are lifted up toward the mothers pubic bone and the trunk of the baby is born by flexing it laterally in the direction of the symphysis pubis. when the baby is all the way out birth is complete and stage 2 ends
what is normal fetal HR?
110-160 (premature babies are closer to 160)
what can be expected in response to spontaneous fetal movement, vaginal examination, fundal pressure, uterine contractions, abdominal palpation, and fetal head compression?
temporary accelerations and slight early decels
what does maternal temperature do to FHR?
FHR increases with maternal temp
fetal circulation is affected by:
1) maternal position
2) maternal BP/oxygenation
3) contractions
4) amniotic fluid quality
what do contractions do to fetal circulation?
contractions decrease the blood flow through the spinal arteries and intervillus space
* most babies can compensate
what happens to fetal respiratory movements during labor?
they decrease during labor
babies prepare to breath at birth by these mechanisms:
1) fetal lung fluid is cleared from the air passages as the baby passes through the birth canal
2) fetal O2 pressure (PO2) decreases
3) arterial carbon dioxide (PCO2) increases
4) arterial pH decreases
5) bicarbonate level decreases
cardiac output peaks after birth
cardiac output peaks ~10-30 minutes after vaginal and cesarean birth and returns to prelabor baseline within the first hour of postpartum
* a drop in the maternal HR accompanies this increase in CO
clotting factors during labor
clotting factors elevated to protect against hemorrhage.
* increased risk for thromboembolism
valsalva maneuver (holding ones breath and tightening abdominal muscles) during labor
this should be discouraged in the second stage
what happens when women in labor do valsalvas maneuver?
- increases intrathoracic pressure
- reduces venous return and increases venous pressure
- CO and BP increase
- pulse slows
fetal hypoxia may occur
how much blood is shunted back into maternal circulation during contractions?
300-500mL
what happens to BP during contractions?
BP increases during contractions
what happens to CO during contractions?
CO increases by 51% above pregnancy values during contractions
what happens with WBC during labor?
elevated WBCs
what happens to hemoglobin and hematocrit levels during labor?
they may be low
hemoglobin 11mg/dl is ok
in an unmedicated woman in the second stage of labor, O2 consumptions increases by how much?
O2 consumption almost doubles
what can hyperventilation during labor cause?
- respiratory alkalosis (increase in pH)
- hypoxia
- hypocapnia (decreased CO2)
what happens to psyche with increased o@ consumption?
anxiety can increase
why may spontaneous voiding be difficult during labor?
1) tissue edema caused by pressure from the presenting part
2) discomfort
3) analgesia
4) embarrassment
proteinuria during labor
+1 ok
increased protein excretion can occur due to muscle tissue breakdown from the physical work of labor
how are perineal lacerations classified?
1 - 4 degree
first degree laceration
laceration that extends skin and structures superficial to the muscle
second degree laceration
laceration that extends through the muscles of the perineal body
third degree laceration
laceration that extends into the anal sphincter muscle
fourth degree laceration
laceration that extends completely through the anal sphincter and the rectal mucosa
where does the latent stage of stage 1 labor often occur
home
nullips present earlier than multips
may come to triage and be sent back home
what is assessed in the first stage of labor?
- labor pattern
- cervical exam
- ROM status
- NST
- VS
characteristics of true labor:
1) contractions occur regularly, become stronger, and are increasingly painful
2) cervix changes
3) contractions are more intense with ambulation
4) presenting part becomes more engaged which eases breathing but puts pressure on the bladder
what changes with the cervix in true labor?
1) bloody show
2) cervix moved anteriorly
3) slow dilation/effacement in latent labor
4) faster dilation/effacement in active phase (faster in multip than in primip)
what are characteristics of false labor?
1) contractions irregular or become irregular over a period of time
2) contractions stop with ambulation
3) cervix may soften but no progressive dilation/effacement; often stays in posterior position
4) fetus not engaged in pelvis
how is a ROM assessed?
1) nitrazine paper
2) sterile speculum
3) ferning
nursing activities when pts are admitted in first stage of labor:
1) begin IOL/augmentation/monitor spontaneous labor
2) admission paperwork, teaching, labs
3) assess and prep for c/s prn
4) fetal monitoring
5) SBAR to providers prn
6) physically and emotionally support pt and support persons
who is responsible for emergency equipment/delivery equipment when a pt is admitted in first stage of labor
L&D nurse
study meds from P.31
cervical ripening
1) outpatient or inpatient foley balloon or cooks balloon (mechanical dilation)/laminaria
2) outpatient or inpatient misoprostol
3) cervidil
4) oxytocin (if positive CST)
cervidil (Dinoprostone, prostaglandin E2)
vaginal insert to ripen cervix
10mg PV (vaginal insert) - leave in for 12-24 hours (remove if ROM or signs of fetal compromise)
misoprostol (prostaglandin E1)
medication used to ripen cervix
100mcg PO or PV q 2-4hrs (monitor for fetal well-being)
oxytocin (IOL)
can be use to induce labor
start with 0.5 - 2 mU, titrate by 0.5-2 mU q 30mins until contractions are 2-3 mins apart
(monitor for fetal well-being)
AROM
- artificial rupture of membranes
- done during labor augmentation
when using nitrazine paper to detect amniotic fluid, what color will the paper turn if positive?
blue-green to deep blue
(pH 6.5-7.5)
nursing care in the second stage of labor
1) SBAR to provider/anesthesiologist
2) coach pushing efforts, encourage pt and support persons
3) prep room for delivery
4) assist provider with position change PRN
5) assist with operative vaginal delivery prn
what does prepping the room for delivery in stage 2 include?
1) have PPH meds available prn
2) SBAR to NICU prn
3) check warmer/turn on
what tools can be used to extract a baby vaginally?
1) forceps
2) vacuum extractor
responsibilities of a pre-op RN (c/s):
1) admit patient
2) start IV
3) send labs
4) SBAR to provider
5) confirm reason for c/s
6) ensure consents signed
7) prep pt for c/s
responsibilities of circulating nurse (c/s):
1) assist in OR with positioning for anesthesia
2) prep pt in OR
3) try to decrease anxiety by talking them through what they will see, feel, etc.)
responsibilities of ICN RN (c/s):
1) catch baby
2) APGARs
3) initial resuscitation
4) warm, dry, swaddle
responsibility of PACU RN (c/s):
recover pt and baby x 2hrs
external cephalic version
- procedure to flip baby from breech/transverse to vertex
- terbutaline if often used to relax uterus prior to procedure
when is an external cephalic version performed?
typically 37+ weeks
RNs role in external cephalic version:
1) give terb
2) assist with ultrasound prn
3) emotional support for pt/family/support person
4) monitor fetus after procedure
5) emergency c/s care prn
TOLAC
trial of labor after c/s
* increased risk of uterine rupture
* no use of prostaglandins for IOL or augmentation
VBAC
vaginal birth after c/s
what is involved with OB triage for someone presenting saying they are in labor?
1) ask pt why they think they are in labor
2) fetal movement assessment
3) frequency and duration of contractions and how long they have been having contractions
4) assess for vaginal bleeding and mucus plug
5) ROM?
6) review chart for risk factors
