labor Doç Dr Oluş APİ Labour parturition It i s the process where by painful regular uterine activity contraction with progressive cervical effacement and dilatation accompanied by decent of the presenting part leads to expelled of the fetus from the uterus at or beyond 24 or 28 ID: 931708
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Slide1
Normal and abnormal labor
Doç. Dr. Oluş APİ
Slide2Labour (parturition)
It
i
s the process where by painful , regular uterine activity (contraction) with progressive cervical effacement and dilatation accompanied by decent of the presenting part leads to expelled of the fetus from the uterus at or beyond 24 (or 28) completed weeks of pregnancy.
Slide31 LNMP
24 W
28 W
37 W
40W
42W
PTL
Term
Labour
Labour can occur at:
prolonged
Slide4Normal labour:
Spontaneous expulsion, through the natural passages (birth canal) of a single, mature (37-42 completed weeks of pregnancy)
Alive fetus, presenting by vertex, within a reasonable time, without fetal or maternal complications.
Slide5Terms
Fetal lie
the relationship of the long axis of the fetus to that of the mother.
If the two are parallel, then the fetus is said to be in a
longitudinal lie
(present in over 99 percent of labors at term).
If the two are at 90-degree angles to each other, the fetus is said to be in a
transverse lie
.
If the fetal and the maternal axes may cross at a 45-degree angle, forming an
oblique lie
, which is unstable and always becomes longitudinal or transverse during the course of labor.
Slide6Fetal presentation
The portion of the fetal body that is either foremost within the birth canal or in closest proximity to it
In longitudinal lies, the presenting part is either
cephalic
or
breech presentations
, respectively.
In transverse lie, the
shoulder
is the presenting part.
Slide7cephalic presentation
breech presentation
shoulder presentation
Slide8Slide9Types of Cephalic presentation
Vertex or occiput presentation
Sinciput presentation
brow presentation
face presentation
Slide10Types of breech presentation
Frank type
Complete type
incomplete type or footling presentation
Slide11Fetal position
Refers to the relationship of an arbitrarily chosen portion of the fetal presenting part to the right or left side of the maternal birth canal.
The dertermining points in
vertex
,
face
, and
breech
presentations are fetal
occiput
,
chin (mentum), and
sacrum respectively.
The presenting part in right or left positions may be directed anteriorly (A), transversely (T), or posteriory (P).
There are six varieties of each of the three presentations.
Slide12Fetal positions of cephalic presentation
Fetal positions of breech presentation
Slide13Diagnosis of fetal presentation and position
Abdominal palpation
(Leopold maneuver)
Vaginal examination
Auscultation
imaging studies: ultrasonography, computed tomography, or magnetic resonance imaging
Slide14Leopold maneuver
Leopold maneuver is established by Leopold in1848
Preparations before examination
Instruct woman to empty her bladder first.
Place woman
in dorsal recumbent position
, supine with knees flexed to relax abdominal muscles. Place a small pillow under the head for comfort.
Drape properly to maintain privacy
Explain procedure to the patient.
Warms hands by rubbing together. (Cold hands can stimulate uterine contractions).
Use the palm for palpation not the fingers
First Maneuver:
To determine fetal part lying in the fundus.
To determine presentation.
procedure:
Using both hands, feel for the fetal part lying in the fundus.
Head
is more firm, hard and round, and is more mobile and ballottable.
Breech
feels as a large, nodular mass.
Slide16Second Maneuver:
To identify location of fetal back.
To determine position.
Procedure
:
One hand is used to steady the uterus on one side of the abdomen while the other hand moves slightly on a circular motion from top to the lower segment of the uterus to feel for the fetal back and small fetal parts.
Use gentle but deep pressure.
Fetal back
is smooth, hard, and resistant surface
Knees and elbows
of fetus feels with a number of small, irregular, mobile parts
Slide17Third Maneuver:
To determine engagement of presenting part.
procedure:
Using thumb and finger, grasp the lower portion of the abdomen above symphisis pubis, press in slightly and make gentle movements from side to side.
The presenting part is engaged if it is not movable.
It is not yet engaged if it is still movable
Slide18Fourth Maneuver:
To determine if the presentation has descended into the pelvis
To determine the position of the fetal presentation
procedure:
Facing foot part of the woman, using the tips of the first three fingers, exerts deep pressure in the direction of the axis of the pelvic inlet
Use both hands.
Fundal Height
Slide20:
N
ot
definitely known – however there are several theories, but none of them is completely proven.
Mechanical theories
:
- uterine distension
Hormonal theories:
Maternal :
progesterone withdrawal
oxytocin
stimulationprostaglandins
serotoninfetal:
fetal cortisolfetal membranes
Neuronal factors:sympathetic- alpha receptor stimulation
Onset of
labour
Slide21Diagnosis
symptoms:
True
labour
pains – colicky pain in the abdomen and back are characterized by
:
False
labour
pain
True
labour
pain
character
Irregular
regular
contractions
Short duration, not progressive
Progressive (increase in frequency and intensity)
Interval between contractions and intensity
Not associated with effacement and dilation of the cervix
Associated with effacement and dilation of the cervix
Changes in the cervix
Not associated with bulging of membranes
Associated with bulging of membranes
Membranes
Relieved by sedation
Not relieved by sedation
Response to analgesia
Not followed by labour
Followed by labour
Labour
Show – blood stained mucous.
SROM
Signs:
palpable or recorded uterine contraction
effacement and dilation of the cervix
formation of forewater
Slide23I-The First stage
:
stage of cervical
effacement and dilatation
Definition
:
the first stage of labour refers to the period from the onset of true uterine contractions to the fully dilation of the cervix, when the diameter of the cervical
os measures 10cm.
STAGES OF LABOUR
Slide24Slide25Duration:
primigravida
= 8-12 h
multigravida
= 6-8 h
Phases of the first stage:
Latent phase:
started when the cervix
dilatated
slowly and reached to about 3cm.
in primigravida = 8h
in multigravida = 4h
- Active phase: rapid dilatation of the cervix to reach 10cm in
primigravda = 4hin
multigravida =2h
Slide26PARTOGRAM: FRIEDMAN’S CURVE
Slide27II-The Second stage of
labour
:
stage of delivery of the fetus.
Definition:
the second stage of
labour
refers to the period from complete cervical dilatation to the birth of the fetus.
Duration:
in
primigravida
=1 hin multigravida = ½ h
however the timing of the second stage is very different to determine and controversial and can be extended as much as there is progress in descent and no harm to the mother or fetus
Slide28The second stage of
labour
ha
s
two phases:
Passive phase
– stage of descent of the presenting part and dilatation of the vagina – due to contraction and retraction of the uterine muscle.
Expulsive phase
– stage of bearing down – due to contraction and retraction of the uterine muscle and voluntary efforts by diaphragm and abdominal muscles.
Slide29CARDINAL MOVEMENTS OF FETAL HEAD
Slide30III-The Third stage of labour:
T
he stage of expulsion of the placenta and membranes
.
Duration:
up to 30 minutes, however the average length of the third stage of
labour
is 10 minutes.
Slide31Mechanism
:
the third stage is made of two phases
:
The first phase: phase of placental separation occurs through the
spongiosa
layer of the
decidua
at the time of expulsion of the baby or very soon afterwards. The shearing force responsible for the separation is the contraction and retraction of the uterus, reducing the uterine volume and the area of the placental site, as the fetus is expelled.
Slide32The second phase: phase of placental expulsion – The separated placenta descends from the upper (active) segment into lower (passive) uterine segment, cervix, and vagina by two mechanisms:
-
Schultze mechanism:(80%)
The placenta delivered as an inverted umbrella with it’s fetal surface presenting first followed by the membranes with retro-placental haematoma.
Mattews – Duncan mechanism: (20%)
The placenta delivered side way and it presents with it’s inferior surface first.
Slide33Slide34Slide35Slide36Slide37Slide38Slide39Slide40Slide41Slide42Slide43Slide44Slide45Slide46Slide47Slide48Slide49Slide50Slide51Placenta
Slide52Slide53DEFINITION
Dystocia
is defined as difficult labor or childbirth.
It may be associated with abnormalities involving:
Abnormalities of the Passage
Abnormalities of the Passenger
Abnormalities of the Powers
or a combination of these factors
ABNORMAL LABOUR: DYSTOCIA
Slide54INCIDENCEOver the last quarter of a century, the cesarean section rate in the United States has risen to approximately 25% of deliveries done each year.
Dystocia
is currently the most common indication for primary cesarean section, and is about three times more common than either non reassuring fetal status or
malpresentation
.
Latent phase
Active phase
2nd
stage
1st stage
max slope
acceleration
dec
Time (hours)
Cervical dilatation (cm)
Friedman labor curve in nulliparous
Slide58ABNORMAL PATTERNS OF LABOR The progress of labor is evaluated primarily through estimates of cervical dilatation and descent of the fetal presenting part. Normal labor patterns in primigravidas and multiparas have been described in detail by Friedman and others.
Slide59Friedman also described four abnormal patterns of labor: (1) prolonged latent phase, (2) protraction disorders (protracted active-phase dilatation and protracted descent), (3) arrest disorders (prolonged deceleration phase, secondary arrest of dilatation, arrest of descent, and failure of descent), and (4) precipitate labor disorders.
Slide601. Prolonged Latent Phase
The latent phase of labor begins with the onset of regular uterine contractions and extends to the beginning of the active phase of cervical dilatation. The duration of the latent phase averages 6.4 hours in
nulliparas
and 4.8 hours in
multiparas
.
Causes of prolonged latent phase include:
excessive sedation or sedation given before the end of the latent phase.
labor beginning with an unfavorable cervix.
uterine dysfunction characterized by weak, irregular, uncoordinated, and ineffective uterine contractions.
fetopelvic disproportion.
Slide612. Protraction Disorders
Protracted cervical dilatation in the active phase of labor
Protracted descent of the fetus constitute the protraction disorders.
Protracted active-phase dilatation is characterized by an abnormally slow rate of dilatation in the active phase,
ie
, less than 1.2 cm/h in
nulliparas
or less than 1.5 cm/h in
multiparas. Protracted descent of the fetus is characterized by a rate of descent under 1 cm/h in
nulliparas or under 2 cm/h in multiparas.
The second stage of labor, which normally averages 20 minutes for parous women and 50 minutes in nulliparous women, is protracted when it exceeds 2 hours in
nulliparas or 1 hour in multiparas, or 3 and 2 hours respectively in the presence of conduction anesthesia.
Slide62The underlying pathogenesis of protracted labor is probably multifactorial. Fetopelvic disproportion. minor malpositions such as occiput posterior.improperly administered conduction anesthesia.
excessive sedation.
pelvic tumors obstructing the birth canal.
Slide633. Arrest Disorders
The four patterns of arrest in labor:
(1) prolonged deceleration, with deceleration phase lasting more than 3 hours in
nulliparas
or more than 1 hour in
multiparas
.
(2) secondary arrest of dilatation, with no progressive cervical dilatation in the active phase of labor for 2 hours or more.
(3) arrest of descent, with descent failing to progress for 1 hour or more.
(4) failure of descent, with descent failing to occur during the deceleration phase of dilatation and during the second stage.
Slide64Causes:
About 50% of patients with arrest disorders demonstrate
fetopelvic
disproportion.
various fetal
malpositions
(
eg, occiput posterior, occiput
transverse, face, or brow).inappropriately administered anesthesia, or excessive sedation.
If fetopelvic disproportion is established, cesarean section is done.
If fetopelvic disproportion is not present and uterine activity is less than optimal, oxytocin stimulation is generally effective in producing further progress.
Slide654. Precipitate Labor DisordersPrecipitate dilatation occurs if cervical dilation occurs at a rate of 5 or more centimeters per hour in a primipara or at 10 cm or more per hour in a multipara. Precipitate descent occurs with descent of the fetal presenting part of 5 cm or more per hour in primparas and 10 cm or more per hour in multiparas.
Slide66Causes:
1-extremely strong uterine contractions
2-low birth canal resistance.
abnormal contractions may be associated with administration of
oxytocin
and
abruptio
placentae.
If oxytocin administration is the cause of abnormal contractions, it may simply be stopped. The problem typically resolves in less than 5 minutes.
If excessive uterine activity is associated with fetal heart rate abnormalities, and this pattern persists despite discontinuation of oxytocin, a b-mimetic such as
terbutaline or ritodrine can be given and magnesium sulfate also
Lacerations of the birth canal are common. maternal amniotic fluid embolism.
predisposing to postpartum hemorrhage.Perinatal mortality is increased secondary to hypoxia, possible intracranial hemorrhage, and risks associated with unattended delivery.
Slide67Uterine rupture may occur in prolonged labor complicated by midpelvic
outlet obstruction, and
vesicovaginal or
rectovaginal
fistula formation may result with pressure necrosis of the surrounding tissues of the birth canal by the fetal head.
Cesarean section is therefore the delivery method of choice in this complication.
Other anatomic abnormalities of the reproductive tract may cause
dystocia
is soft tissue dystocia may be caused by uterine or vaginal congenital anomalies, scarring of the birth canal, pelvic masses, or low implantation of the placenta.
Slide68--Abnormalites
of the
Passenger
**A.
malposition
and
malpresentation
:Fetal malpresentations
are abnormalities of fetal position, presentation, attitude, or lie. They collectively constitute the most common cause of fetal dystocia, occurring in approximately 5% of all labors.
1. Vertex malpositions—a.
Occiput posterior— b. Occiput
transverse—2. Brow presentation—Brow presentations usually are transient fetal presentations with deflexion of the fetal head.
Slide693. Face presentation—In face presentation, the fetal head is fully deflexed from the longitudinal axis. 4. Abnormal fetal lie—In transverse or oblique lie, the long axis of the fetus is perpendicular to or at an angle to the maternal longitudinal axis.
Slide705. Breech presentation**B. fetal macrosomia**C. fetal malformationThe most common malformation is hydrocephalus, enlargement of the fetal abdomen caused by distended bladder, ascites, or abdominal neoplasms; or other fetal masses, including meningomyelocele or cystosarcoma.
Slide71Abnormalities of the Powers
Normal uterine activity during labor:
(1) the relative intensity of contractions is greater in the
fundus
than in the
midportion
or lower uterine segment (this is termed
fundal dominance); (2) the average value of the intensity of contractions is more than 24 mm Hg. (3) contractions are well synchronized in different parts of the uterus; (4) the basal resting pressure of the uterus is between 12 and 15 mm Hg; (5) the frequency of contractions progresses from one every 3–5 minutes to one every 2–3 minutes during the active phase; (6) the duration of effective contraction in active labor approaches 60 seconds; and (7) the rhythm and force of contractions are regular.
Slide72Quantification of uterine activity during labor by: -external tocodynamometry -intrauterine pressure catheter measurement. Uterine dysfunction generally comprises 3 categories:
hypotonic dysfunction,
hypertonic dysfunction,
uncoordinated dysfunction
.
Slide73Hypotonic dysfunction is uterine activity characterized by contraction of the uterus with insufficient force (> 24 mm Hg), irregular or infrequent rhythm, or both. Seen most often in
primigravidas
in the active phase of labor, it may be caused by excessive sedation, early administration of conduction anesthesia, twins,
polyhydramnios
, or
overdistention
of the uterus.
Hypotonic dysfunction responds well to oxytocin
; however, care must be taken to first rule out cephalopelvic disproportion and malpresentation. Active management of labor has been shown to decrease perinatal morbidity and cesarean section rates.
Slide74hypertonic uterine contractions and uncoordinated contraction
often occur together and are characterized by elevated resting tone of the uterus,
dyssynchronous
contractions with elevated tone in the lower uterine segment, and frequent intense uterine contractions. It is generally associated with
abruptio
placentae, overuse of
oxytocin
, cephalopelvic disproportion, fetal malpresentation, and the latent phase of labor.
Treatment:
tocolysis, decrease in oxytocin infusion
cesarean section as indicated for concomitant malpresentation, cephalopelvic disproportion, or fetal distress.