Intrapartum Flashcards
Definition of Intrapartal Period
From contractions that cause cervix to dilate, through delivery of neonate & placenta, +
first 1-4 hours after delivery
Theories of Labor Onset: Progesterone Deprivation Theory
Pregnancy: both estrogen and progesterone increased (from placenta), but ratio of
estrogen low: progesterone high
Estrogen stimulates, progesterone relaxes
Just before labor: ratio shifts
Theories of Labor Onset: Oxytocin Theory
Oxytocin stimulates uterine contractions, but uterus not sensitive until closer to term
Therefore, unlikely oxytocin works alone to cause labor onset
Theories of Labor Onset: Fetal Endocrine Control Theory
Anencephalic fetus: low levels fetal steroids; pregnancy prolonged
? if steroids cause release of precursors to prostaglandins, which stimulate uterus to
contract
Theories of Labor Onset: Prostaglandin Theory
Prostaglandins: lipid substances
Induce contractions at any point in pregnancy
Used for:
1. IUFD (intrauterine fetal demise); suppository form
2. Induced abortion; injectable form
3. Cervical ripening; gel, tampon ( Cervidil), tablet forms
Labor = Myometrial Activity
Feedback loop: stretching of cervix causes increase of oxytocin, which increases
myometrial activity
Fetus distends uterus: ? relationship
In true labor, uterus divides
Upper segment: active & contractile, thickens as labor progresses
Lower segment & cervix: passive, thins and expands as labor progresses
In between 2 areas: physiologic contraction band
lower segment transverse (LST) AKA lower cervical transverse (LCT)
If patient desires trial of labor after Cesarean (TOLAC) to attempt a vaginal birth after
Cesarean (VBAC), must have this uterine incision
Vertical Uterine Incisions
Higher risk of uterine rupture with labor
In upper segment (contractile)
Will have future repeat C/S
Effacement of Cervix
Taking-up of internal os and cervical canal into uterine sidewalls
Usually precedes dilatation in primigravidas
Express in percentage: 0% - 100%
Some subjectivity
Dilation of Cervix
Longitudinal muscle fibers of uterus pull upward over baby’s head
Combined with pressure from bag of waters (BOW)
Cervix dilation from 0 cm to 10 (“complete”, “fully”)
“Pushing”
Once completely dilated, woman pushes to expel fetus & placenta
Using intra-abdominal pressure
Must be “complete” or can bruise/tear cervix; exhaustion ensues
Pushing Causes Fetal Head to Descend to Pelvic Floor
Head meets perineal structure; pressure causes it to thin from 5 cm thick to 1 cm
Thin = less blood = natural physiologic anesthesia
Anus everts, exposing internal rectal wall
Premonitory Signs of Labor: Lightening
- Fetus settles into inlet (becomes “engaged”)
- Uterus seems to move downward (“dropped)
Breathe easier
More pelvic pressure
More leg cramps/pain
More venous stasis
Premonitory Signs of Labor: Braxton-Hicks Contractions
Irregular, intermittent contractions
Experienced throughout pregnancy
Pain in abdomen or groin
Can become uncomfortable
Purpose: cervical ripening
Premonitory Signs of Labor: Cervical Ripening
Ripe cervix: soft, anterior, slightly effaced and dilated
Non-pregnant: cervix feels like tip of nose
Pregnant: like lower lip
Ripe: like pudding
Ripening important re: induction decisions (unlikely to be successful if unripe)
Bishop Score: Cervical Ripening
Cervical Ripening Balloon
No drugs needed ( mechanical pressure)
Eliminates side effects
Silicone balloons adapt to cervical contour
Easily placed & removed ( foleys can be used)
Premonitory Signs of Labor: Bloody Show
Mucus plug expelled; exposed capillaries bleed
Consistency: bloody mucus
Watery bleeding NEVER normal
Labor usually begins 24-48 hours
Confusion if recent vaginal exam
Premonitory Signs of Labor: ROM (Rupture of Membranes)
- SROM: Spontaneous Rupture of Membranes
-
AROM: Artificial Rupture of Membranes, via amniotomy
Most common L & D procedure
No pain endings in BOW (bag of water)
Additional terms: -
PROM: Premature Rupture of Membranes;
>1 hour from ROM to labor onset - PPROM: Preterm, Premature Rupture of Membranes
Prolonged ROM
anytime ROM >24 hours; increased risk of ascending infection
Chorioamnionitis: infected BOW; fever, tenderness, foul-smelling & cloudy amniotic
fluid
Sterile Speculum exam:
to check if BOW broke
rests ½ hour
Pooling, nitrazine, ferning
Normal fluid: clear, bloody streaks; not meconium-stained or port wine color
Umbilical Cord Prolapse
Major OB emergency
R/O: after ROM, check FHTs; if low, suspect prolapse
Glove hand, insert into vagina, push upward; place patient in Trendelenburg or hands &
knees (relieve pressure on cord)
Premonitory Signs of Labor: “Nesting Instinct”
Sudden burst of energy
24 – 48 hours prior to labor
Cause unknown
Woman “feathers her nest”
Warn not to over-exert
Premonitory Signs of Labor: “Other”
- Weight loss of 1-3 #
Fluid & electrolyte shifts
“progesterone deprivation theory” - More backache & sacroiliac pressure
Relaxin influencing pelvis - N/V, diarrhea
More room in pelvis
Clear liquid absorption unchanged; may vomit solids (aspiration risk)
True Labor
- Cervix progressively effaces/dilates
- Contractions regular, become closer, longer, stronger over time
- Pain begins in back, radiates to abdomen
- Ambulation intensifies
False Labor
- No progressive effacement/dilation
- Contractions irregular, do not become closer, longer, stronger
- Pain chiefly lower abdomen or groin
- Ambulation relieves
Stages of Labor & Birth
- First Stage - True labor until 10 centimeters dilation
- Second Stage - Complete dilation thru birth of neonate
- Third Stage - Birth of neonate thru birth of placenta
- Fourth Stage - First 1-4 hours after delivery
Critical Factors in Labor: The 5 P’s (traditional)
- Passageway (pelvis)
- Passenger (fetus)
- Powers (contractions)
- Psyche (mental status of the woman)
- Position (…of the woman)
Additional Critical Factors
Philosophy (low tech, high touch)
Partners (support persons)
Patience (respect for the natural timing of birth)
Patient Preparation (knowledge base)
Pain Management (comfort care)
Passageway: Pelvis
True pelvis: bony birth canal; must be adequate size, shape
False pelvis: nothing to do with OB; holds up abdominal contents
3 planes
Inlet (linea terminalis)
Midpelvis (ischial spines)
Outlet (ischial tuberosities)
1933, Caldwell-Malloy Pelvic Types: Inlet Shape
- Gynecoid: “female” pelvis, 50% women; all diameters adequate for birth
- Android: “male” pelvis, 20% women; OP (occiput posterior), long labors, C/S
- Anthropoid: OP, but usually adequate; long AP diameter compensates
- Platypelloid: flat pelvis, rare, inadequate for birth
Getting an OP to Rotate to OA
Occiput Posterior (OP) sunny side up Occiput Anterior (OA)
- Hands+knees
- Lunging
Gynecoid pelvis measurments
- Inlet
Clinical Pelvimetry: measure diagonal conjugate (11.5 cm)
- Midpelvis
Clinical Pelvimetry: ischial spines blunt, pelvic sidewalls straight, sacrum hollow (curved),
coccyx freely-movable
- Outlet
Bi-ischial diameter: 8 cm or >
Pubic arch: at least 90 degrees
Passenger (Fetus)
- Must fit through bony pelvis
Most are head-first
Largest part
Least compressible
If head delivers, delivery of body rarely delayed
Fetal head molds to accommodate pelvis
Diameters of Fetal Skull:
- Biparietal Diameter (BPD)
- Suboccipitobregmatic Diameter
Vertex: Most Common
Suboccipitobregmatic diameter presents to pelvis
Head well-flexed; chin onto chest
Fetal Lie
Relationship of fetus to long axis of mother
Normal lie: longitudinal
Fetus’ long axis in line with mother’s long axis
Abnormal lies: transverse & oblique
Oblique is unstable
Fetal Attitude
Refers to posturing of joints & relation of fetal parts to one another
Normal attitude: flexion
Deflexed = larger diameters of fetus meet pelvis
Fetal Presentation: “Presenting Part”
Part of fetus closest to internal os
At term:
Cephalic (head), 96-97%
Breech (buttocks), about 3%
Arm or shoulder, <1%
Transverse lie
Risks: Vaginal Breech Delivery
Few trained in methods
After-coming head
Increased risk hypoxic events/cerebral palsy
Increased risk umbilical cord prolapse
Preemie breech should never be delivered vaginally
Compound Presentation:
More than 1 part presenting, i.e. baby’s hand on top of head
Larger diameter to fit through pelvis
Malpresentation:
Anything other than cephalic presentation
Can lead to difficult labor & birth
*ECV External Cephalic Version
Relationship of Fetus to Pelvis
- Engagement: widest diameter of presenting part reaches or passes through inlet
Confirms adequacy of inlet
2 weeks before term in primigravida
Can happen before or during labor in multipara - Station: relationship of head to ischial spines
Confirms adequacy of midpelvic plane
Forceps/Vacuum Extraction
Can only be done if fetus descends to “0” station
Otherwise, C/S
Mother must be completely dilated
Forceps/Vacuum Extraction Reasons
Fetal distress #1 reason
Maternal exhaustion
Maternal cardiac disease
Poor pushing (epidural)/prolonged 2nd stage
Forceps
MD only
Open or closed blades
Different types
Preemies
Breeches
Term vertex
Usually with vaginal delivery, but also C/S
Pulling sensation; good anesthesia needed
More room; episiotomy needed
Like big “spoons”: 2 curves
1 fits around head
Other conforms to shape of pelvis/birth canal
Must know landmarks to avoid injury to baby
Mother still pushes
Gentle traction
Deliver head to perineum or fully deliver
Vacuum Extraction Delivery
CNMs can also perform
Same reasons & usage as forceps, but less precise landmarks
Must use safe amount of suction
LOA - left occiput anterior - most common
LOT - left occiput transverse
LOP - left occiput posterior
ROA - right occiput anterior
ROT - right occiput transverse
ROP - right occiput posterior
The Powers (Contractions)
Intermittent shortening of muscle
Propel fetus through birth canal
Involuntary; action independent of mother’s will & extrauterine nervous control
Phases of Contraction - increment, acme, decrement
Dystocia
“dys-” = difficult or painful
“-tocia” = birth
Abnormal labor patterns can lead to dystocia
Hypertonic: uterus doesn’t relax sufficiently between contractions
Hypotonic: uterus doesn’t contract strongly enough to be effective
Friedman Labor Curves: Ideal Labor
Friedman Labor Curve: Effect of Station
Catecholamines
Stress hormones; released in response to anxiety & fear
Constrict blood vessels, including those to uterus
Uterine muscle anoxic, causing pain (#2 cause of pain in labor)
High catecholamine levels block release of oxytocin and may prolong labor
Endorphins
Morphine-like substances; come from pituitary gland & brain
Laboring women have higher levels than non-pregnant
Relaxation, touch, massage, activity can raise levels
Goal: minimize catecholamines, maximize endorphins
Decrease anxiety, use comfort measures, walk
Position (…of the woman)
Primary consideration: don’t lie on back in labor
Vena cava compression worse in labor
If cardiac output falls, can’t perfuse uteroplacental unit
Alternate positions frequently; use upright & lateral positions
Contractions more intense, but not more painful
Fetal head descends quicker (gravity)
Labor may be shorter
Fetal diameters correspond better to pelvic diameters
First stage - Latent Phase (early labor)
Onset of regular contractions until 3 cm
Nullipara: 8.6 hours, no >20 hours
Multipara: 5.3 hours, no >14 hours
Contractions: every 10-20 minutes x 15-20 seconds, mild—become every 5-7 minutes x
30-40 seconds, moderate
Average 40 mm Hg; resting tone 10 mm Hg
Good time to review CB preparation
Latent Phase - Pain control
Gate control theory of pain relief:
Stimulate peripheral nerves, message of pain can’t reach brain
Examples: TENS units, effleurage, distraction, relaxation techniques, massage
Alternative Pain Relief
Aromatherapy
Hydrotherapy
Massage
Latent Phase -
Breathing patterns:
rhythmic chest breathing
Slow rate 8/min
Modified rate 16-20/min
Latent Phase - Nursing care
Time contractions
Support efforts
Monitor breathing/relaxation
Conserve energy (many are excited, talkative)
Clear fluids/empty bladder every 2 hours
Latent Phase - vitals
Maternal VS hourly, except T every 4 hours
If ROM, T hourly with pulse
FHT auscultation
Hourly if low-risk
½-hourly if high-risk
Note fetal activity
Note uterine contraction pattern every ½ hour
Labor pain: #1 cause is cervical changes
Medications in Latent Phase
Labor not well-established
Narcotics/epidurals can slow labor down
Can’t give po meds
Options:
1. Vistaril 50 mg IM (sedative)
2. Inhalation analgesia (nitrous oxide)
Active Phase (accelerated phase)
Labor well-established
Dilates from 4-7 cm
Nullipara dilates 1.2 cm/hr
Multipara dilates 1.5 cm/hr
Descent is progressive
Contractions: every 2-3 minutes x 60 seconds, strong
If ROM, increase in strength
Active Phase Breathing
Breathing patterns: combined, rhythmic chest or shallow (“he-he-hoo”)
“count down” contractions
Remind her that labor is intermittent
Active Phase - nursing care
- Mouth care
- Stroke arms and legs
- Encourage efforts
- Intake/output; full bladder impedes descent
Active Phase
Medications:
Labor well-established, so unlikely to diminish
Narcotics “take the edge off” pain:
Nubain (nalbuphene) 10 mg IM or IV every 3-6 hours
Inhalation anesthesia
Nitrous oxide
Regional anesthesia
Epidural most common
60-80% in major city hospitals
Epidural Anesthesia: The Good
Relief of labor pain
Allows for rest
Decreases catecholamines
Can be awake if C/S
Partner may prefer this method
Epidural Anesthesia: The Bad, part 1
#1: ↓ BP due to peripheral vasodilation
Inadvertent spinal + possible headache
Immobility, unless “walking epidural”
May ↓ contractions → more pitocin
May ↑ length of 2nd stage → forceps/vacuum
? ↑ OP babies, ? ↑ C/S
Epidural Anesthesia: The Bad, part 2
Unable to void; may need catheter
“Spotty” blocks
Mild itching
May ↓ neonate’s ability to breastfeed
Maternal fever → blood cultures/antibiotics in neonate
Epidural Anesthesia: The Ugly (Contraindications)
Bleeding disorders/anticoagulants
Mother low volume (PIH)
Thrombocytopenia
Infections near site (i.e., herpes)
Other Regional Anesthetics
Spinal
Injected inside dura
Uses less medicine & works faster than epidural
More likely than epidural to decrease BP
Used for C/S, not labor
Pudendal
Local anesthetic injected into pudendal nerve, near ischial spine
Usually given 2nd stage
Relieves pain around vagina/rectum
Good for forceps, prolonged repairs
Paracervical
Local anesthetic injected into the cervix, during labor
Can cause FHT to drop
Could accidentally inject fetus
Active Phase - vitals
Check maternal VS hourly; T every 4 hours, unless ROM (hourly, with pulse)
Check FHT every 30 minutes in low-risk; every 15 minutes high-risk
Note uterine contraction pattern every 30 minutes
Transition Phase
Patient dilates from 8-10 cm
Contractions strong and close together: every 1 ½ - 2 minutes, lasting 60 seconds or more
Short phase
Nullipara: no >2 hours
Multipara: no >1 hour
Descent progressive
Nullipara: 1 cm/hour
Multipara: 2 cm/hour
Transition Phase - breathing and nursing care
Breathing patterns: pant-blow during contractions & rhythmic chest breathing in-between
Head descends; urge to push
Patient irritable, discouraged, over-whelmed
Give specific instructions
Remind her that baby is almost here
Encourage her
Remain with her
Transition Phase - special considerations
Physical sensations: N/V, belching, chills, trembling, sweating, difficulty relaxing
Special considerations:
Hyperventilation: tingling, dizzy, light-headed
Rebreathe exhaled air between contractions
Back labor: small of back, difficult to relax, increase in tension
Warm or cold compresses
Counterpressure to small of back
Increase in bloody show
Transition Phase - Vitals
Check maternal VS every 30 minutes
Check FHT every 30 minutes low-risk; every 15 minutes high-risk
Second Stage of Labor
Nullipara: 48-174 minutes, 66 average
Multipara: 6-66 minutes, 24 average
“precip. packs”
Prolonged second stage = >2 hours
Pushing sensation: pressure of fetal head on sacral & obturator nerves
Woman feels relieved; birth near & actively involved
Some fight pushing; fear, loss of control
Second Stage of Labor
Coach efforts:
open glottis pushing
Physical sensations: vaginal fullness, rectal pressure, burning, stretching
Instruct to stop pushing at birth of head; use pant-blow
Second Stage of Labor- Vitals
Check maternal VS every 15 minutes
Check FHT every 5-15 minutes (most RNs check after each contraction)
Check delivery equipment; O2, suction, Code Pink Team/Code Pink Box, turn on warmer
Second Stage: Crowning
Ring of fire ; episiotomy performed
Cardinal Movements (Mechanisms) of Labor
- Engagement
- Descent
- Flexion
- Internal rotation
- Extension
- External rotation/restitution
- External rotation/shoulder rotation
- Expulsion
Extension (4., 5.):
: head meets resistance of pelvic floor + mechanical
movement of vulva anterior & forward;
head passes under pubic bone &
occiput, then brow, then face emerge
External rotation/restitution (6.):
head
rotates 45 degrees
External rotation/shoulder rotation (7.):
head rotates additional 45 degrees; head & shoulders lined up
Expulsion (7., 8.): anterior shoulder
meets underside of pubic symphysis
& slips under it; delivery attendant lifts
baby up & posterior shoulder born; body flexes laterally
Third Stage of Labor
Baby born, uterus contracts: less surface for placental attachment, hematoma forms
between placenta & decidua
Signs of separation usually 5 minutes after birth; 30 minutes or > = retained placenta
Globular shape to uterus
Fundus rises
Gush of blood
Amount of cord lengthens
Third Stage of Labor - placenta delivery
Patient bears down; attendant aids with gentle traction
Always check to see if placenta complete
> 30 min - manual removal of placenta
Fourth Stage of Labor
1-4 hours after delivery
BP returns to prelabor level
Pulse slightly lower than labor
FF @ U or below, midline
No evidence of PPH
Variation in emotional state
Hungry, thirsty, shaking chills, hypotonic bladder
Interview/Risk Assessment
Why in L & D: labor? EDC?
Contracting: when began? Pain?
Fluid leakage or bleeding?
Problems during pregnancy? Medical problems? Any surgeries? Recent exposure to illness ?
Problems during pregnancy? Medical problems? Any surgeries? Recent exposure to
illness?
Take any medications? Allergies to meds.?
Baby moving normally?
Last ate and drank?
Admission Care - VS
Get VS
Elevated BP suggests pre-eclampsia
Elevated T suggests infection
Pulse >100 suggests hypovolemia
Urine Dipstick
1+ proteinuria or > suggests pre-eclampsia
1-2+ glycosuria or > suggests diabetes
CBC, Type & Screen
Leopold’s Maneuvers
Check FHT/place external monitors
Admission Care
Time frequency/duration of contractions
Check fundus for strength of contractions
If likely ROM, Nitrazine & prepare ferning slide
Some settings: check cervical dilation & effacement
Start IV or place heplock
EFM in Low-Risk Women
- *>85% low-risk have EFM**
1. Does not decrease # perinatal deaths
2. Does not decrease # with CP
3. Does not decrease # admitted to NICU - *Continuous monitoring**
1. Increases risk of Vacuum or forceps delivery
2. Increases risk of C/S
3. Increases risk of infection
External monitoring (indirect)
2 belts
Tocodynanometer (“toco”); placed over fundus, picks up contractions
Ultrasound transducer; placed over baby’s chest or back, opening/closing of valves of
heart read as FHTs
More subject to artifact
Can use on anyone
Internal Monitoring (direct)
2 types, placed inside uterus; must have ROM & be dilated at least 2 cm
IUPC: intrauterine pressure catheter; goes between fetus’ head & wall of uterus,
squeezed during contractions, transducer picks up strength in mm Hg
FSE: fetal scalp electrode; internal spiral electrode, attaches to fetus’ head & picks up
electrical activity of heart, reads it as FHT
Less subject to artifact
Basics of EFM: “Dr. C. Bravado”
- Determine Risk
- Contractions
- Baseline
- Rate
- And
- Variability
- Accelerations (periodic change of FHR)
- Decelerations (periodic change of FHR)
Early
Late
Variable - Overall impression
Determine Risk
Interpret tracing within context of clinical circumstances
Patterns change over time; regular re-evaluation needed
Contractions
# in 10 minute period averaged over 30 minute period
Normal < or = 5/10 minutes
Tachysystole > 5/10 minutes
Duration, intensity, rest between also important
Baseline Rate
Mean FHR rounded to increments of 5 bpm over 10 minutes, excluding accelerations,
decelerations, marked variability
Bradycardia: baseline < 110 bpm
Tachycardia: baseline > 160 bpm
Baseline Bradycardia
Baseline <110
#1 cause: fetal hypoxia
Other causes uncommon: congenital heart block, maternal use of beta blockers
Baseline Tachycardia
Baseline >160
#1 cause: maternal/fetal fever
Other causes: infection, fetal hypoxia, tocolytic drugs (Terbutaline)
Variability
Baseline fluctuations, irregular in amplitude & frequency
Peak-to-trough in bpm, seen over 10 minutes
Parasympathetic/sympathetic nervous system
Categories of Variability
Absent: amplitude range undetected
Minimal: range < 5 bpm use
Moderate: range 6-25 bpm
Marked: range > 25 bpm
