Normal and abnormal - PowerPoint Presentation

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Normal and abnormal labor

Doç. Dr. Oluş APİ

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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) completed weeks of pregnancy.

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1 LNMP

24 W

28 W

37 W

40W

42W

PTL

Term

Labour

Labour can occur at:

prolonged

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Normal 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.

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Terms

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.

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Fetal 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.

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cephalic presentation

breech presentation

shoulder presentation

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Types of Cephalic presentation

Vertex or occiput presentation

Sinciput presentation

brow presentation

face presentation

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Types of breech presentation

Frank type

Complete type

incomplete type or footling presentation

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Fetal 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.

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Fetal positions of cephalic presentation

Fetal positions of breech presentation

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Diagnosis of fetal presentation and position

Abdominal palpation

(Leopold maneuver)

Vaginal examination

Auscultation

imaging studies: ultrasonography, computed tomography, or magnetic resonance imaging

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Leopold 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

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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.

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Second 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

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Third 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

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Fourth 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.

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Fundal Height

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:

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

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Diagnosis

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

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Show – blood stained mucous.

SROM

Signs:

palpable or recorded uterine contraction

effacement and dilation of the cervix

formation of forewater

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I-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

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Duration:

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

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PARTOGRAM: FRIEDMAN’S CURVE

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II-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

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The 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.

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CARDINAL MOVEMENTS OF FETAL HEAD

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III-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.

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Mechanism

:

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.

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The 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.

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Placenta

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DEFINITION

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

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INCIDENCEOver 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

.

 

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Latent phase

Active phase

2nd

stage

1st stage

max slope

acceleration

dec

Time (hours)

Cervical dilatation (cm)

Friedman labor curve in nulliparous

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ABNORMAL 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.

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Friedman 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.

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1. 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.

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2. 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.

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The 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.

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3. 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.

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Causes:

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.

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4. 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.

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Causes:

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.

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Uterine 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.

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--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.

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3. 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.

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5. 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.

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Abnormalities 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.

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Quantification of uterine activity during labor by: -external tocodynamometry -intrauterine pressure catheter measurement. Uterine dysfunction generally comprises 3 categories:

hypotonic dysfunction,

hypertonic dysfunction,

uncoordinated dysfunction

.

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Hypotonic 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.

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hypertonic 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.