Normal Labor and Delivery
The Obstetrics and Gynecology Hospital of
Fudan University
Jing-Xin Ding
Definition
• Labor is the period from the onset of regular
uterine contractions until expulsion of the fetus
and the placenta, and it is defined as that
occurring after 28 completed weeks of gestation.
• Preterm delivery occurring after 28 weeks and before
37 completed weeks of gestation. In some developing
countries, this time point has been advanced to 20
gestational weeks.
• Term delivery occurring after 37 weeks and before 42
completed weeks of gestation.
• Postterm delivery occurring after 42 completed weeks
of gestation.
CHAPTER 1 THE HYPOTHESIS OF PARTURITION
INITIATION
1. Mechanic theory
UTERINE QUIESCENCE During the early stage of
pregnancy, a remarkably period of myometrial
quiescence is imposed.
CERVICAL SOFTENING By the end of pregnancy,
easily distensible, increase in tissue compliance
Uterine awakening or activation
• During the end stage of pregnancy, the fetus
compressed the lower segment and cervix, and
mechanic effect induced the initiation of labor.
2. Endocrine theory
• Some key endocrine proteins that control
contractility.
• These proteins include the oxytocin and its
receptor, prostaglandin and its receptor,
progesterone, and endothelin.
Fetal Contributions to Initiation of
Parturition
• The ability of the fetus to provide endocrine signals that initiate parturition
has been demonstrated in several species.
• This signal was shown to come from the fetal hypothalamic-pituitary-adrenal
axis .
3. Neuromediator theory
• The uterine contraction is controlled by the
autonomic nerve.
• It is still uncertain the role of autonomic nerve in
the initiation of labor.
Summary
• Culmination of a series of
biochemical changes in
the uterus and cervix.
• Many hypothesis:
• Not fully defined.
Mechanic theory
Endocrine theory
Neuromediator theory
CHAPTER 2
THE FACTORS DECIDING LABOR AND DELIVERY
Force of the
labor
Birth canal
Fetus
Mental and
psychological
factors
I Force of the labor
•
•
Uterine Contractions — Main force
Maternal intra-abdominal pressure and the
contranction of levator ani — Ancillary forces
Characteristics of the uterine
contractions
•
•
•
•
Rhythmicity
Symmetry
Polarity
Retraction effect
1. Rhythmicity
Each contraction increase progressively in intensity
and maintains the maxium intensity and then
diminishes gradually.
• the uterine baseline tone -- from 8 to 12 mm Hg
• 25 mm Hg at commencement of labor to 50 mm
Hg at the end of first stage
• During second-stage labor, aided by maternal
pushing, contractions of 100 to 150 mm Hg are
typical.
• At the beginning, the contracts occurs every 5-6
minutes, and last 30 s. With the progression of
labor, frequency increases to every 1-2 min and
the duration increases to 60 s when the cervix is
fully dilated.
2. Symmetry
The normal contractile
wave of labor originates
near the uterine end of
the fallopian tubes. Thus,
these areas act as
"pacemakers".
Contractions spread from the pacemaker area throughout the
uterus at 2 cm/sec, depolarizing the whole uterus within
15 seconds.
3. Polarity
•
•
•
Intensity is greatest in the fundus
Diminishes in the lower uterus.
Presumably, this descending gradient of
pressure serves to direct fetal descent toward
the cervix.
4. Retraction effect
• The muscle fiber retracts after contractions, and
the cavity of the uterus becomes small, and the
fetus is forced to descend.
Maternal intra-abdominal pressure -pushing
• Contraction of the abdominal muscles
simultaneously with forced respiratory efforts with
the glottis closed is referred to as pushing.
• After the cervix is dilated fully, the most important
force.
• Accomplishes little in the first stage. It exhausts the
mother, and its associated increased intrauterine
pressures may be harmful to the fetus.
The contraction of levator ani
contributes to:
• the internal rotation, extention and expulsion of
the fetal head in the 2nd stage of labor
• the delivery of placenta in the 3rd stage of labor.
II Birth canal
• Bony Pelvis
• The soft birthing canal
Bony Pelvis
The false pelvis above and the true
pelvis below the linea terminalis.
The true pelvis is formed by the
sacrum and coccyx posteriorly and by
the ischium and pubis laterally and
anteriorly.
Pelvic Planes
1.The pelvic inlet plane
2.The mid plane of pelvis--the plane of least
diameter
3.The pelvic outlet plane
The pelvic inlet plane
• bordered by the pubic
crest anteriorly, the
iliopectineal line of the
innominate bones laterally,
and the promontory of the
sacrum posteriorly.
Four diameters: anteroposterior, transverse, and
two oblique diameters.
• The obstetric conjugate of
the inlet -- distance
between the promontory of
the sacrum and the
symphysis pubis. -- 11 cm.
• The transverse diameter is constructed at right angles to
the obstetrical conjugate and represents the greatest
distance between the linea terminalis on either side.
• 2 oblique diameters extends from one of the sacroiliac
synchondroses to the iliopectineal eminence on the
opposite side.
The mid plane of pelvis--the plane of least
diameter
• The most important -- most arrest of descent
occur at this level.
It is bordered by the lower edge
of the pubis anteriorly, the
ischial spines and sacrospinous
ligaments laterally, and the
lower sacrum posteriorly.
• The interspinous diameter, 10 cm or slightly
greater-- the smallest pelvic diameter.
The plane of the pelvic outlet
• 2 approximately triangular areas with a common base
• The apex of the posterior triangle is at the tip of the sacrum, and
the lateral boundaries are the sacrosciatic ligaments and the
ischial tuberosities.
 The anterior triangle is
formed by the area under
the pubic arch.
Important Diameters:
• The transverse (bituberous) diameter extends between the
inner surfaces of the ischial tuberosities —an average of 9 cm
• The posterior sagittal diameter — from the middle of the
transverse diameter to the sacrococcygeal joint —an average
of 8.5 cm
 If bituberous diameter < 9 cm ,
but the bituberous diameter +
the posterior sagittal diameter
>15 cm — delivered through
the posterior triangle.
Pelvic axis
— an imaginary curved line that passes through the
centers of the various diameters of the pelvis.
The pelvic axis first goes inferior and posterior, and then
inferior, and then inferior and anterior.
Inclination of pelvis
— The angle which the plane of the pelvic inlet makes
with the horizontal plane when the patient is
standing.
The degree is usually 60 °, if it is too much, the
engagement and delivery is difficult.
The soft birthing canal
• the lower uterine
segments
• the cervix
• the vagina
• the pelvic floor
Formation of the Lower Uterine Segments
— derived from the isthmus which is about 1 cm in
nonpregnant uterus, and when the labor is started,
with regular contractions of the upper uterine segment,
it distended to 7 to 10cm.
the Physiological Retraction Ring
• As a result of the lower segment thinning and
concomitant upper segment thickening, a boundary
between the two is marked by a ridge on the inner
uterine surface—the physiological retraction ring.
Cervical Changes
• two fundamental changes—effacement and
dilatation
• For an average-sized fetal head to pass through
the cervix, its canal must dilate to a diameter of
approximately 10 cm.
Effacement of cervix
• Cervical effacement is "obliteration" or "taking
up" of the cervix.
• A length of about 2-3 cm canal -- a circular orifice
with almost paper-thin edges.
Dilatation of cervix
• Forebag of amnionic fluid is the leading portion of
the amnionic sac and fluid located in front of the
presenting part.
• As uterine contractions cause pressure on the
membranes, the hydrostatic action of the amnionic
sac in turn dilates the cervical canal.
A. Before labor, the primigravid
cervix is long and undilated
in contrast to that of the
multipara, which has
dilatation of the internal and
external os.
B. As effacement begins, the
multiparous cervix shows
dilatation and funneling of
the internal os. This is less
apparent in the primigravid
cervix.
C. As complete effacement is
achieved in the primigravid
cervix, dilation is minimal.
The reverse is true in the
multipara.
Pelvic Floor Changes during Labor
• Stretching of levator ani muscle fibers.
• Thinning of the central portion of the perineum,
which becomes transformed from a wedgeshaped, 5-cm-thick mass of tissue to a thin,
almost transparent membranous structure less
than 1 cm thick.
III Fetus
•
•
•
Size of fetus
Fetal lie, presentation and position
Fetal abnormalities
FETAL HEAD
Important sutures and fontanelles
• two frontal, two parietal, and two temporal
bones, along with the occipital bone.
Sutures
The membraneoccupied spaces
between the
cranial bones are
known as sutures.
Fontanelles
The membrane-filled spaces
located at the point where the
sutures intersect are known as
fontanelles.
 The anterior fontanelle (bregma) is at the intersection of the
sagittal, frontal, and coronal sutures. It is diamond shaped and
measures approximately 2×3cm, and it is much larger than the
posterior fontanelle.
 The posterior fontanelle is Y- or T-shaped and is found at the
junction of the sagittal and lambdoid sutures.
• Clinically, they are useful in diagnosing the
fetal head position.
Diameters
 Occipitofrontal Diameter (11.3cm),
extends from the external occipital
protuberance to the glabella. The fetus
usually engage by this diameter.
• Suboccipitobregmatic Diameter
(9.5cm),-- extends from the
undersurface of the occipital bone at
the junction with the neck to the center
of the anterior fontanelle. -- the
presenting anteroposterior diameter
when the head is well flexed, and it is
the shortest anteroposterior diameter .
• Occipitomental Diameter
(13.3cm), the presenting
anteroposterior diameter in a
brow presentation and the
longest anteroposterior diameter
of the head; it extends from the
vertex to the chin.
• Biparietal Diameter (9.3cm), the
largest transverse diameter; it
extends between the parietal
bones.
• This diameter detected by
antenatal ultrasonic examination
was used to estimate the size of
the fetus.
2. Fetal lie and presentation
• Fetal Lie. The lie is the relation of the long axis of
the fetus to that of the mother, and is either
longitudinal or transverse.
• Fetal Presentation. The presenting part is that
portion of the fetal body that is either foremost
within the birth canal or in closest proximity to it.
3. Fetal abnormalities
• When certain part of fetus is enlarged in fetal
abnormalities, for example, conjoined twins,
hydrocephalus, dystocia will occur.
IV Maternal mental and psychological factors
• Psychologic support to the women during labor is very
important.
• The provision of continuous psychologic support during
labour by doulas, as well as nurses, family or friends is
associated with improved maternal and fetal health and
a variety of other benefits.
• A doula, also known as a labour coach, is a nonmedical
person who assists a woman before, during or after
childbirth, as well as her partner and/or family by
providing information, physical assistance and emotional
support.
CHAPTER 3 MECHANISM OF LABOR WITH OCCIPUT
PRESENTATION
• The positional changes in the presenting part
required to navigate the pelvic canal constitute
the mechanisms of labor.
• Left occiput anterior (LOA) position is the most
common fetal position
• The cardinal movements of labor are
engagement, descent, flexion, internal rotation,
extension, external rotation, and expulsion.
ENGAGEMENT
• The mechanism by which the biparietal
diameter—the greatest transverse diameter in an
occiput presentation—passes through the pelvic
inlet is designated engagement.
• In nulliparous women, the fetal head engage 1 or
2 weeks before labor.
• In multiparous women, the fetal head usually
engage after the onset of labor.
A normal-sized head
usually does not
engage with its sagittal
suture directed
anteroposteriorly.
Instead, the fetal head
usually enters the
pelvic inlet either
transversely or
obliquely.
DESCENT
• This movement is the first requisite for birth of
the newborn.
• In nulliparas, engagement may take place before
the onset of labor, and further descent may not
follow until the onset of the second stage.
• In multiparous women, descent usually begins
with engagement.
Descent is brought about by one or more of four
forces:
(1) pressure of the amnionic fluid,
(2) direct pressure of the fundus upon the breech
with contractions,
(3) bearing down efforts of maternal abdominal
muscles
(4) extension and straightening of the fetal body.
FLEXION
• As soon as the descending head meets resistance,
whether from the cervix, walls of the pelvis, or
pelvic floor, flexion of the head normally results.
• In this movement, the chin is brought into more
intimate contact with the fetal thorax, and the
appreciably shorter suboccipitobregmatic diameter is
substituted for the longer occipitofrontal diameter.
INTERNAL
ROTATION
• This movement consists of
a turning of the head in
such a manner that the
occiput gradually moves
toward the symphysis pubis
anteriorly from its original
position.
EXTENSION
• After internal rotation, the sharply flexed head
reaches the vulva and undergoes extension.
• When the head presses upon the pelvic floor,
however, two forces come into play.
• The first, exerted by the uterus, acts more
posteriorly, and the second, supplied by the
resistant pelvic floor and the symphysis, acts
more anteriorly.
• The resultant vector is in the direction of the
vulvar opening, thereby causing head extension.
• With progressive distention of the perineum and vaginal
opening, an increasingly larger portion of the occiput
gradually appears. The head is born as the occiput,
bregma, forehead, nose, mouth, and finally the chin pass
successively over the anterior margin of the perineum.
EXTERNAL ROTATION
• The delivered head next undergoes restitution.
• If the occiput was originally directed toward the
left, it rotates toward the left.
• Restitution of the head to the oblique position is
followed by completion of external rotation to the
transverse position, a movement that corresponds to
rotation of the fetal body, serving to bring its bisacromial
diameter into relation with the anteroposterior diameter
of the pelvic outlet. Thus, one shoulder is anterior
behind the symphysis and the other is posterior.
EXPULSION
• Almost immediately after
external rotation, the anterior
shoulder appears under the
symphysis pubis, and the
perineum soon becomes
distended by the posterior
shoulder. After delivery of the
shoulders, the rest of the body
quickly passes.
• During labor, these movements are sequential
but also show great temporal overlap.
• For example, as part of the process of
engagement, there is both flexion and descent of
the head.
• As a result, the fetus is transformed into a
cylinder, with the smallest possible cross section
passing through the birth canal.
Summary
• Preterm delivery occurring after 28 weeks and before
37 completed weeks of gestation. In some developing
countries, this time point has been advanced to 20
gestational weeks.
• Term delivery occurring after 37 weeks and before 42
completed weeks of gestation.
• Postterm delivery occurring after 42 completed weeks
of gestation.
THE FACTORS DECIDING LABOR AND DELIVERY
Force of the
labor
Birth canal
Fetus
Mental and
psychological
factors
Characteristics of the uterine
contractions
•
•
•
•
Rhythmicity
Symmetry
Polarity
Retraction effect
Formation of the Lower Uterine Segments
— derived from the isthmus which is about 1 cm in
nonpregnant uterus, and when the labor is started,
with regular contractions of the upper uterine segment,
it distended to 7 to 10cm.
the Physiological Retraction Ring
• As a result of the lower segment thinning and
concomitant upper segment thickening, a boundary
between the two is marked by a ridge on the inner
uterine surface—the physiological retraction ring.
Fetal lie and presentation
• Fetal Lie. The lie is the relation of the long axis of
the fetus to that of the mother, and is either
longitudinal or transverse.
• Fetal Presentation. The presenting part is that
portion of the fetal body that is either foremost
within the birth canal or in closest proximity to it.
• The positional changes in the presenting part
required to navigate the pelvic canal constitute
the mechanisms of labor.
• The cardinal movements of labor are engagement,
descent, flexion, internal rotation, extension,
external rotation, and expulsion.
CHAPTER 4
DIAGNOSIS OF THREATENED LABOR
AND LABOR
THREATENED LABOR
• Before actual labor begins, a number of
physiologic preparatory events usually occur.
And these are called threatened labor.
The manifestation of threatened labor
• Lightening
• False Labor
• Bloody show
Lightening
• Two or more weeks before labor, the fetal head
in most primigravid women settles into the brim
of the pelvis. In multigravida, this often does not
occur until early in labor.
• Lightening may be noted by the mother as a
flattening of the upper abdomen and an
increased prominence of the lower abdomen.
False Labor
• During the last 4 to 8 weeks of pregnancy, the uterus undergoes
irregular contractions that normally are painless.
• Such contractions appear unpredictably and sporadically and can
be rhythmic and of mild intensity. In the last month of pregnancy,
these contractions may occur more frequently, and with greater
intensity.
• These Braxton Hicks contractions are considered false labor in
that they are not associated with progressive cervical dilatation
or effacement.
• They may serve, however, a physiologic role in preparing the
uterus and cervix for true labor.
Bloody show
• As a result of cervical effacement, the
mucous plug within the cervical canal may
be released. The onset of labor may thus be
heralded by the passage of a small amount
of blood-tinged mucus from the vagina
(“bloody show”).
In Labor
• It is defined as progressive cervical effacement
and dilatation resulting from regular uterine
contractions that occur at least every 5 minutes
and last 30 to 60 seconds.
STAGES OF LABOR
• Total stage of labor is from the onset of regular
uterine contractions to the delivery of the baby
and placenta.
3 stages of labor
• The first stage is from the onset of true labor to complete
dilation of the cervix.
primiparous patients: 11-12h, multiparous patients 6-8h.
• The second stage is from complete dilation of the cervix to
the birth of the baby.
primiparous patients: 1-2h, less than 2 h. multiparous patients
much faster, less than 1h.
• The third stage is from the birth of the baby to delivery of the
placenta.
5-15min, less than 30 minutes.
CHAPTER 5 CLINICAL MANIFESTATION AND
MANAGEMENT OF FIRST STAGE OF LABOR
CLINICAL MANIFESTATION OF THE FIRST STAGE
1. Regular uterine contraction.
• From the onset of labor: occurs every 5-6 minutes and last
about 30 seconds.
• With the progression of labor, the uterine contractions
increase progressively in intensity. Frequency increases to
every 2-3 min. Duration increases to 50-60 seconds.
• When the cervix is nearly fully dilated, the contractions
last to 1min or even longer, and rest for only 1-2 min.
2. Dilatation of cervix
-- determined by vaginal examination.
Effacement of the cervix – Dilation
10cm at the end of the 1st stage
3. Descent of fetal head
• -- Determined by vaginal
examination.
• The level—or station—of
the presenting fetal part in
the birth canal is
described in relationship
to the ischial spines.
• At the level of the spines -zero (0) station.
• 3,2and 1 cm above the
ischial spines, the
designation is –3, –2, –1.
• 1, 2,3 and 4cm blow the
spines, as the presenting
fetal part descends, it is
then +1, +2, +3, +4.
4. Rupture of membranes
• Rupture of membranes usually occurs when the
cervix is nearly fully dilated.
MANAGEMENT OF THE FIRST STAGE OF
LABOR
• On admission the general
condition of the patient is assessed,
her pulse rate and blood pressure
are recorded, and her urine is
tested for protein.
• By abdominal examination the
presentation and position of the
fetus, and the relation of the
presenting part to the brim of the
pelvis, are determined.
• Abdominal examination will also
show the frequency and strength
of the uterine contractions. The
fetal heart rate is counted for a
full minute, and any abnormality
of rate or rhythm is noted.
• A vaginal examination will
show the degree of
dilatation of the cervix,
whether the membrane
are intact or ruptured,
and the level and position
of the presenting part.
Partogram
• Once the labor has become established, all events during
labor are noted on a partogram—a most useful graphical
record of the course of labor.
• The alarm line
• The management line
Uterine Activity
• Uterine contractions should be monitored every
30 minutes by palpation for their frequency,
duration, and intensity.
• This either an external tocodynamometercan be
achieved electronically using or an internal
pressure catheter in the amniotic cavity.
Fetal Monitoring
• The fetal heart rate should be evaluated by either
auscultation with a DeLee stethoscope, by external
monitoring with Doppler equipment, or by internal
monitoring with a fetal scalp electrode.
• In patients with no significant obstetric risk factors, the
fetal heart rate should be auscultated or the electronic
monitor tracing evaluated every 1-2h in the latent phase
of labor, and at least every 15-30 minutes in the active
phase of the first stage of labor and at least every 15
minutes in the second stage of labor.
DILATION OF CERVIX AND DESCENT OF FETAL
HEAD
Measurement of progress
• During the first stage, the progress of labor may
be measured in terms of cervical effacement,
cervical dilatation, and descent of the fetal head.
Phases
• Latent phase, during which cervical effacement and early
dilatation(to 3cm) occur
• Active phase, during which more rapid cervical dilatation occurs,
the cervix dilate from 3cm to 10cm.
The active phase has 3
component parts
• acceleration phase the cervix dilates
from 3-4cm, normally takes 1h and 30
min.
• maximum acceleration phase the cervix
dilates from 4-9cm, normally takes 2h.
• deceleration phase the cervix dilates
from 9-10cm, normally takes 30 min.
Length
• The length of the first stage may vary in
relation to parity; primiparous patients
generally experience a longer first stage
than do multiparous patients.
• This phase normally takes 8h, and the
maximum is 16 h in primiparous patients.
• The active phase begins when the cervix is 3 cm
dilated. The minimal dilatation during the active
phase of the first stage is nearly the same for
primiparous and multiparous women: 1 and
1.2cm/hour, respectively.
• This phase normally takes 4h, and the maximum
is 8 h.
Descent of fetal head
• The level—or station—of the presenting fetal
part in the birth canal is described in relationship
to the ischial spines.
• The descent of fetal head is not obvious in the
latent phase, and is accelerated in the active
phase, usually 0.86cm/h.
Rupture of membranes
• Rupture of membranes usually occurs when the
cervix is nearly fully dilated.
• Once the membrane is ruptured, the fetal heart
should be monitored, and the color and amount
of Amnionic Fluid should be noted.
• And the time of rupture should be recorded.
Blood Pressure
• During uterine contractions, the maternal blood
pressure usually elevated 5-10 mmHg. The blood
pressure should be monitored every 4-6 hours
once the labor is started.
Maternal Position
• If the head is engaged there is no need for the patient to
remain in bed during early labor. If she is up and about,
the weight of the liquor and fetus helps to dilate the
cervix, and pressure on the lower segment stimulates
the uterus to contract.
• If she is lying in bed, the lateral recumbent position
should be encouraged to ensure perfusion of the
uteroplacental unit.
Vaginal Examination
• During the latent phase, every 4 hours
• In the active phase, every 2 hours
• Cervical effacement and dilatation, the station and
position of the presenting part should be recorded.
Amniotomy (The artificial rupture of fetal
membranes )
• Provide information on the volume of amniotic fluid and
the presence or absence of meconium. In addition,
rupture of the membranes may cause an increase in
uterine contractility.
• Amniotomy incurs risks of chorioamnionitis if labor is
prolonged and of umbilical cord compression or cord
prolapse if the presenting part is not engaged.
CHAPTER 6 CLINICAL MANIFESTATION AND
MANAGEMENT OF SECOND STAGE OF LABOR
• This stage begins when cervical dilatation is
complete and ends with fetal delivery.
CLINICAL MANIFESTATION
• Bear down -- the urge to defecate.
• Uterine contractions may now last 1minute
or longer and recur at an interval no longer
than 1 minute.
• The abdominal pressure, together with the
uterine contractile force, combines to expel
the fetus.
Head visible on vulval gapping -- the fetal head is seen at the
vulva at the height of each contraction. Between the
contractions the elastic tone of the perineal muscles push the
head back .
• The perineal body and vulval outlet become more
and more stretched, and the encirclement of the
largest head diameter by the vulvar ring is known
as crowning of head.
• Descent, flexion, internal rotation, extension,
external rotation, and expulsion.
• The second stage generally takes from 1 to 2
hours in primigravid women and from 5 to 60
minutes in multigravid women.
MANAGEMENT OF THE SECOND STAGE
Fetal Monitoring
• During the second stage, the fetal heart rate
should be monitored continuously or evaluated
every 5-10 minutes.
Bearing Down
• With each contraction, the mother should be
encouraged to hold her breath and bear down
with expulsive efforts.
Vaginal Examination
• Progress should be recorded approximately every
30 minutes during the second stage. -- the
descent and flexion of the presenting part, the
extent of internal rotation.
• Cervix is no longer palpable.
Delivery of the Fetus
• When delivery is imminent, the
patient is usually placed in the
lithotomy position, and the skin
over the lower abdomen, vulva,
anus, and upper thighs is
cleansed with an antiseptic
solution.
The modified Ritgen maneuver
• Prevent it being born suddenly, and the head must be kept flexed.
• One hand is used to exert forward pressure on the chin of the fetus through
the perineum. Concurrently, the other hand exerts pressure superiorly
against the occiput. The downward pressure increases flexion of the head
and allows a controlled delivery. This maneuver is designated the modified
Ritgen maneuver.
• After the airway has been cleared, an index finger
is used to check whether the umbilical cord
encircles the neck. If so, the cord can usually be
slipped over the infant’s head. If the cord is too
tight, it can be cut between two clamps.
• Then the shoulders descend and
rotate into the anteroposterior
diameter of the pelvis.
• Delivery of the anterior shoulder is
aided by gentle downward
traction on the externally rotated
head. The brachial plexus may be
injured if excessive force is used.
The posterior shoulder is delivered
by elevating the head. Finally, the
body is slowly extracted by traction
on the shoulders.
EPISIOTOMY
Episiotomy -- incision of the perineum.
Indication:
• The perineum is tight or the fetus is big.
• To accelate the delivery of the fetus.
Median midline episiotomy or Postero-lateral
episiotomy.
CHAPTER 7 CLINICAL MANIFESTATION AND
MANAGEMENT OF THIRD STAGE OF LABOR
clinical manifestation: placental separation
Signs of placental separation
(1) A fresh show of blood from the vagina,
(2) The fundus of the uterus rises up and the uterus
becomes firm and globular.
(3) The umbilical cord lengthens outside the vagina,
(4) The cord does not retract when press the lower
segment of the uterus.
2 Mechanisms of placenta separation and expulsion
• Schultze mechanism more
common, the fetal side of the
placenta expelled first.
• Duncan mechanism less common,
the maternal side of the placenta
expelled first.
Management
• Management of the newborn’s respiratory tract
The mouth and pharynx are sucked clear with a
mucus extractor. A healthy baby breathes and
cries very soon after it is born.
 Management of the cord
The cord is clamped and cut within 15 to 20 seconds.
Delayed cord clamping can result in neonatal
hyperbilirubinemia.
The newborn is then placed under an infant warmer
A plastic clamp that is safe, efficient, and fairly inexpensive,
is widely used.
APGAR SCORE
• This scoring system is a useful clinical tool to
identify those neonates who require resuscitation
as well as to assess the effectiveness of
resuscitative measures.
APGAR SCORE
Sign
0
1
2
1. Heart rate
Absent
<100 beats/min
>100 beats/min
2. Respiratory effort
Absent
Slow, irregular
Good, crying
3. Muscle tone
Flaccid
Some flexion of extremities
Active motion
4. Reflex irritability
(response to stimulation of
sole of foot)
None
Grimace
Vigorous cry
5. Color
Pale, blue
Body,pink; extremities,
blue
Completely pink
• Apgar score 8-10 Normal
• Apgar score 4-7 asphyxia livida , blue asphyxia—
clear air, artificial respiration，give O2,drug
• Apgar score 0-3 asphyxia pallida, white
asphyxia—resuscitation, endotracheal intubation
• The 1-minute Apgar score reflects the need for
immediate resuscitation.
• The 5-minute score, and particularly the change
in score between 1 and 5 minutes, is a useful
index of the effectiveness of resuscitative efforts.
• The 5-minute Apgar score also has prognostic
significance for neonatal survival.
 Assist the delivery of placenta
The mother may be asked to bear down, and the intraabdominal pressure may be adequate to expel the placenta.
If these efforts fail, then pressure is exerted with the hand on
the fundus to propel the detached placenta into the vagina.
Traction on the umbilical cord must not be used to pull the
placenta out of the uterus.
• The placenta is then gently lifted away from the
introitus. Care is taken to prevent the membranes
from being torn off and left behind. If the
membranes start to tear, they are grasped with a
clamp and removed by gentle teasing.
• Examination of the Placenta and the membrane
To ensure its complete removal and to detect placental
abnormalities.
• Examination of the soft birth canal
The cervix and vagina should be thoroughly inspected for
lacerations and surgical repair performed if necessary.
• Prophylaxis of postpartum hemorrhage
Uterine massage and the use of oxytocin.
If the patient is at risk of postpartum, manual
removal of the placenta may be necessary.
Summary
THREATENED LABOR
• Before actual labor begins, a number of
physiologic preparatory events usually occur.
And these are called threatened labor.
The manifestation of threatened labor
• Lightening
• False Labor
• Bloody show
In Labor
• It is defined as progressive cervical effacement
and dilatation resulting from regular uterine
contractions that occur at least every 5 minutes
and last 30 to 60 seconds.
STAGES OF LABOR
• Total stage of labor is from the onset of regular
uterine contractions to the delivery of the baby
and placenta.
3 stages of labor
• The first stage is from the onset of true labor to
complete dilation of the cervix.
primiparous patients: 11-12h, multiparous patients 6-8h.
• The second stage is from complete dilation of the cervix
to the birth of the baby.
primiparous patients: 1-2h, less than 2 h. multiparous
patients much faster, less than 1h.
• The third stage is from the birth of the baby to delivery
of the placenta.
5-15min, less than 30 minutes.
Phases
• Latent phase, during which cervical effacement and early
dilatation(to 3cm) occur
• Active phase, during which more rapid cervical dilatation occurs,
the cervix dilate from 3cm to 10cm.
The active phase has 3
component parts
• acceleration phase the cervix dilates
from 3-4cm, normally takes 1h and 30
min.
• maximum acceleration phase the cervix
dilates from 4-9cm, normally takes 2h.
• deceleration phase the cervix dilates
from 9-10cm, normally takes 30 min.
Length
• The length of the first stage may vary in
relation to parity; primiparous patients
generally experience a longer first stage
than do multiparous patients.
• This phase normally takes 8h, and the
maximum is 16 h in primiparous patients.
• The active phase begins when the cervix is 3 cm
dilated. The minimal dilatation during the active
phase of the first stage is nearly the same for
primiparous and multiparous women: 1 and
1.2cm/hour, respectively.
• This phase normally takes 4h, and the maximum
is 8 h.
Head visible on vulval gapping -- the fetal head is seen at the
vulva at the height of each contraction. Between the
contractions the elastic tone of the perineal muscles push the
head back .
• The perineal body and vulval outlet become more
and more stretched, and the encirclement of the
largest head diameter by the vulvar ring is known
as crowning of head.
• Descent, flexion, internal rotation, extension,
external rotation, and expulsion.
• The second stage generally takes from 1 to 2
hours in primigravid women and from 5 to 60
minutes in multigravid women.
Signs of placental separation
(1) A fresh show of blood from the vagina,
(2) The fundus of the uterus rises up and the uterus
becomes firm and globular.
(3) The umbilical cord lengthens outside the vagina,
(4) The cord does not retract when press the lower
segment of the uterus.
APGAR SCORE
• This scoring system is a useful clinical tool to
identify those neonates who require resuscitation
as well as to assess the effectiveness of
resuscitative measures.
APGAR SCORE
Sign
0
1
2
1. Heart rate
Absent
<100 beats/min
>100 beats/min
2. Respiratory effort
Absent
Slow, irregular
Good, crying
3. Muscle tone
Flaccid
Some flexion of extremities
Active motion
4. Reflex irritability
(response to stimulation of
sole of foot)
None
Grimace
Vigorous cry
5. Color
Pale, blue
Body,pink; extremities,
blue
Completely pink
• Apgar score 8-10 Normal
• Apgar score 4-7 asphyxia livida , blue asphyxia—
clear air, artificial respiration，give O2,drug
• Apgar score 0-3 asphyxia pallida, white
asphyxia—resuscitation, endotracheal intubation
丁景新
Jingxin Ding
Email: djxdd@sina.com