Normal
Labor and
Birth
The Five “Ps” of Labor
o Passageway: maternal
bony pelvis and tissues
o Passenger: the fetus
o Powers: primary and
secondary forces of labor
o Position: maternal
position
o Psyche: psychological
component of mother
The Passage
o Pelvis type
o Pelvis size
o Cervical effacement
o Cervical dilation
Cervical Effacement and Dilation
o Uterus divides into upper
(contractile) and lower
(passive) segments.
o Effacement: taking up of
internal os and cervical canal
into uterine side walls
o Dilatation: Widening of
cervical os from opening < 1
cm to approximately 10 cm.
Formation of Lower Uterine Segment
Primigravida: Effacement usually occurs before dilation
Multipara: dilation & effacement usually occur together
The Passenger
o
o
o
o
o
Fetal head
Fetal attitude
Fetal Lie
Fetal presentation
Fetal position
The Passenger: Fetal Head
o Skull vault bones
§ 2 - Frontal
§ 2 - Parietal
§ 1 - Occipital
o Sutures
§ Sagittal
§ Frontal
§ Coronal
§ Lambdoidal
The Passenger: Fetal Head
Molding of the fetal head in cephalic positions
The Passenger: Fetal Head
o Landmarks
§ Mentum (Chin)
§ Sinciput (Brow)
§ Anterior Fontanelle
(Bregma)
§ Vertex
§ Posterior Fontanelle
§ Occiput
The passenger: The Fetal Head
Anteroposterior diameters
of the fetal skull
Transverse diameters
of the fetal skull
Passenger: Fetal Attitude
o Relation of fetal parts to
one another
o Normal attitude is flexion
of neck, arms and legs
o Hyperextension is
abnormal attitude
o Fetal attitude changes can
cause larger diameter of
fetal head to present to
pelvis
Passenger: Fetal Lie
o Relationship of longitudinal axis of fetus
to longitudinal axis of mother
§ Longitudinal lie: fetal spine is parallel to
mother’s spine
l Transverse lie: fetal spine is at right angles to
mother’s spine
l
Vertex (head first) is most common, but
breech (buttocks or feet first), transverse
(laterally across uterus) and oblique
(diagonally across uterus) also possible
Passenger: Fetal Presentation
o Presentation refers to fetal part entering pelvis first
o Most common is cephalic but breech and shoulder
also occur.
o Cephalic presentations: vertex, military, brow or
face
o Breech presentations: complete, frank or footling
o Shoulder presentation: occurs rarely; presenting
part is shoulder, arm, back, abdomen or side
Passenger: Cephalic Presentations
o Vertex
o Face
§ Most common
§ Hyperextended
§ Head completely flexed
§ Small diameter
§ Smallest diameter
presents
presents
§ Face is presenting part
§ Occiput is the
o Military
presenting part
§ Neither flexed or
o Brow
extended
§ Partially extended
§ Larger diameter
§ Largest diameter
presents
presents
§ Sinciput is presenting
§ Top of head is
part
presenting part
Passenger: Malpresentations
o Complete Breech
§ Fetus sitting with legs
crossed in pelvis
§ Knees and hips are
flexed
§ Buttocks and feet are
presenting part
o Frank Breech
§ Hips are flexed with
knees extended
§ Buttocks are the
presenting part
o Footling Breech
§ Hips and legs are
extended
§ Feet are the presenting
part
§ Can be a double or
single footling
o Shoulder Presentation
§ AKA transverse lie
§ Presenting part is
shoulder, arm, back,
abdomen or side
Passenger: Fetal Position
o Fetal landmarks of presenting fetal part to are used to
describe position of fetus in relation to the front
(anterior), back (posterior), or sides (right or left) of
maternal pelvis.
l
l
l
l
Fetal Landmarks
O = Occiput (vertex)
M = Mentum (face)
S = Sacrum (breech)
A = Acromion process
(shoulder)
l
l
l
l
l
Maternal Pelvis
R = Right side
L = Left side
A = Anterior
P = Posterior
T = Transverse
Categories of Presentations
ROA= Right Occipital
Anterior
LOA= Left Occipital
Anterior
LOT = Right Occipital
Transverse
Categories of Presentations
ROP= Right Occipital
Posterior
LMA= Left Mentum
Anterior
LSP = Left Sacrum Posterior
The Passenger: Fetal Station
o Relationship of presenting part
to imaginary line drawn
between ischial spines of
maternal pelvis
o Ischial spines mark narrowest
diameter through which fetus
must pass
o The station at the level of
ischial spines is 0
o If presenting part is higher than
spines, it is a negative number.
o If presenting part is lower than
spines, it is a positive number.
Passenger: Engagement
› Engagement occurs when largest diameter
of presenting part reaches pelvic inlet and
can be felt on vaginal exam
› Floating: If presenting part directed
towards pelvis but can easily be moved out
of inlet
› Ballotable: When presenting part dips into
inlet but can be displaced with upward
pressure from examiner s fingers
› Engaged: If presenting part fixed in pelvic
inlet and cannot be dislodged
The Power:
Uterine
Contractions
Power: Forces of Labor
o Primary forces are involuntary contractions of
uterine muscle fibers, stimulated by
pacemaker in upper uterine segment
o Secondary forces consist of the voluntary use
of abdominal muscles during the second stage
of labor to facilitate the descent and delivery
of the fetus
Power: Primary Forces of Labor
o Effacement:
§ With each UC, muscles of upper uterine segment
shorten, exerting longitudinal traction on cervix
causing thinning and drawing up of internal os and
cervical canal into uterine side walls
§ Measured from 0 to 100%
o Dilation (aka dilatation)
§ As uterus elongates with UCs, fetal body
straightens out and exerts pressure against lower
uterine segment and cervix. Cervix opens as a
result, allowing for birth of fetus
§ Measured from 0 to 10 cm
Power: Primary Forces of Labor
Position of Laboring Woman
o Affects: circulation, fatigue,
comfort
o Upright position (walking,
sitting. kneeling, squatting)
§ Promotes descent of fetus
§ Improves blood flow
§ Relieves backache
§ Straightens axis of birth
canal
§ Increases pelvic outlet
Psyche
o Preparation for childbirth
o Sociocultural heritage
o Previous childbirth
experience
o Support from significant
others
o Emotional status
o Environmental influence
Premonitory Signs of Labor
o
o
o
o
o
o
Lightening
Bloody show
Painful Braxton Hicks
Cervical ripening
Diarrhea
Energy burst
False vs True Labor
False Labor
o Regular contractions
o Decrease in frequency and
intensity
o Discomfort in lower
abdomen and groin
o Activitychange alters Ucs
o UCs stop when sleeping
o No appreciable cervical
change
o Sedation decreases UCs
o Show usually not present
True Labor
o Regular contractions
o Progressive frequency and
intensity
o Discomfort begins in back,
radiating to abdomen
o Activity increases UCs;
continue when sleeping
o Progressive effacement and
dilation of cervix
o Sedation does not stop UCs
o Show usually present
Leopold’s First Maneuver
Leopold’s Second Maneuver
Leopold’s Third Maneuver
Leopold’s Fourth Maneuver
Stages of Labor and Birth
o First stage:begins with onset of true labor and ends
with complete dilation
o Second stage: begins with complete dilation and
ends with birth of infant
o Third stage: begins with expulsion of infant and
ends with expulsion of placenta
o Fourth stage: begins with expulsion of placenta,
lasting 1 to 4 hours
First Stage of Labor
Latent Phase
§ Cervical dilation: 0 - 3 cm
§ Duration: 8.6 hrs in nullipara - 5.3 hrs in multipara
§ Contraction frequency: 3 - 30 minutes; may be
irregular
§ Contraction duration: 30 - 40 seconds
§ Contraction intensity: Mild by palpation, 25 - 40 mm
Hg by IUPC
§ Physical sensations: Menstrual-like cramps, low
backache, light bloody show, diarrhea, possible SROM
§ Maternal behavior: Able to ambulate and talk through
contractions; pain controlled fairly well
First Stage of Labor
Active Phase
§ Cervical dilation: 4 - 7 cm
§ Duration: 4.6 hrs in nullipara - 2.4 hrs in multipara
§ Contraction frequency: 2 - 5 minutes
§ Contraction duration: 40 - 60 seconds
§ Contraction intensity: Moderate to strong by
palpation, 50 - 70 mm Hg by IUPC
§ Physical sensations: Increasing discomfort, trembling
of thighs/legs; pressure on bladder and rectum;
backache with occipitoposterior fetal position.
§ Maternal behavior: Working to keep control; quieter
First Stage of Labor
Transition
§ Cervical dilation: 8 - 10 cm
§ Duration: 3.6 hrs in nullipara - variable in multipara
§ Contraction frequency: 1.5 - 2 minutes
§ Contraction duration: 60 - 90 seconds
§ Contraction intensity: Strong by palpation, 70 - 90 mm
Hg by IUPC
§ Physical sensations: Increased bloody show; urge to
push; increased rectal pressure, ROM may occur.
§ Maternal behavior: Ambulation difficult; may be
irritable, agitated; self-absorbed; needs more support;
may feel discouraged and unable to cope
Cardinal Movements of Labor
o
o
o
o
o
o
o
Descent
Flexion
Internal Rotation
Extension
Restitution
External Rotation
Expulsion
Cardinal Movements of Labor
o
Adaptations made by fetus to maneuver
through pelvis during labor and birth.
o In occiput (most common presentation),
movements occur in following order:
1. Engagement of presenting part occurs
2. Descent of fetus into pelvis
3. Flexion of fetal head (often occurs with
descent)
4. Internal rotation of fetal head to
accommodate widest diameter of maternal
pelvis
Cardinal Movements of Labor
5. Extension of fetal head as it comes
under symphysis
6. Restitution as head turns 45˚ to untwist
neck
7. External rotation viewed as head turns
45˚ to align shoulders with widest
diameter of maternal pelvis
8. Expulsion as anterior shoulder slips
under pubis
Second Stage of Labor
o
o
o
o
o
o
o
10 cm to birth
Duration: up to 3 hrs in nullipara and 0 - 30 min in
multipara
Contraction frequency: 2 - 3 minutes
Contraction duration: 40 - 60 seconds
Contraction intensity: Strong by palpation, 70 - 100 mm
Hg by IUPC
Physical sensations: As presenting part descends, urge to
push increases; increased rectal and perineal pressure;
sensation of burning, tearing and stretching of vagina and
perineum
Maternal behavior: Excited and eager to push; reluctant,
ineffective pushing
Lacerations
o Lacerations to perineum or surrounding tissue may
occur during childbirth; 3rd and 4th˚ lacerations most
commonly occur after midline episiotomy performed
§ 1st˚ involves only epidermal layers; if no bleeding
may not need repair
§ 2nd˚ involves epidermal and muscle/fascia
involvement requires suturing
§ 3rd˚ extends into rectal sphincter
§ 4th˚ extends through rectal mucosa
Third Stage of Labor
o Birth of infant to birth of
placenta
o Duration: 5 - 30 minutes
o Physical sensations: Mild
uterine contractions; feeling of
fullness in vagina as placenta
expelled
o Maternal behavior: Attention
focused on newborn; feelings of
relief; euphoria
Apgar Score
o Quick method to assess fetal adaptation to
extrauterine life
o Five criteria scored at 1 and 5 minutes after birth
with 0,1 or 2 pts given for each criteria
§ Appearance:
§ Pulse:
§ Grimace:
§ Activity:
§ Respirations:
Color
Heart rate
Reflex irritabilty
Muscle tone
Respiratory effort
o ≥ 8: minimal intervention
o 4-7: suction, tactile stimulation, oxygen
o 0-3: resuscitation
Placental Separation
o
Uterine contraction after birth of infant diminishes
surface area of placental attachment, causing
placenta to begin to separate.
o Bleeding occurs causing hematoma to form
between placenta and uterine wall
o Signs of separation:
1. Globular-shaped uterus
2. Gush of blood
3. Rise of fundus
4. Protrusion of umbilical cord
Placental Separation
Placental Delivery
o When signs of separation appear:
§ Ask woman to bear down
§ If undelivered, firm, gentle traction applied to cord
with pressure on fundus
§ Shiny Schultz: Separation occurs from inner to
outer margins of placenta allowing fetal side to
deliver first
§ Dirty Duncan: Separation occurs from outer
margins first, causing placenta to roll up with
maternal surface first.
§ Considered retained when 30 minutes have elapsed
without delivery of placenta
Fourth Stage of Labor
o One to four hours following birth
o Tremendous hemodynamic changes occur
o Blood not lost at birth (250 - 500 ml) is
redistributed into venous beds
o B P drops, pulse increases
o Uterus is contracted and is midline
o Fundus is usually midway between umbilicus and
symphysis pubis
o Shaking chill is common
o Hypotonic bladder may lead to urinary retention