NORMAL LABOUR
Prof. OSMAN DONIA
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NORMAL LABOUR
DEFINITIONS
Labor "Tocia":
Labor is the process of expulsion of the fetus from the uterus
after viability.
Viability:
Is a reasonable chance of the fetus for extrauterine survival
(28 weeks in Egypt, 22 weeks in USA)
Normal labor “Eutocia”:
Normal labour entails the spontaneous expulsion of a single
living full term fetus, in a vertex cephalic presentation,
through the natural birth canal after spontaneous onset of
true labor pains, without assistance and without
complications to the mother or fetus.
The average duration of normal labour:
12-18 hours in the primigravida
6-10 hours in the multigravida
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INCIDENCE:
It should be noted that “normal labor” is a
retrospective diagnosis. The majority of labours are
normal however the true incidence is difficult to
estimate.
POSITIONS:
1.
2.
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Left and Right occipitoanterior (LOA and ROA).
Left and Right occipitotransverse (LOT and ROT).
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STAGES OF LABOUR
First stage: From start of labour to full dilatation
of cervix. It is divided into latent phase and
active phase
Second stage: From full dilatation to birth of
baby
Third stage: From the time of delivery of fetus to
expulsion of placenta and membranes
Fourth stage: Upto 6hrs after birth to rule out
post partum haemorrhage
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DIAMETERS OF THE INLET
DIAMETERS OF THE OUTLET
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FOETAL SKULL
FOETAL SKULL
FOETAL SKULL
Summary of presenting diameters with
different presentations
Vertex
Suboccipito–bregmatic
9.5 cm
Deflexed OP
Occipito–frontal
11.5 cm
Brow
Mento–vertico
13 cm
Face
Submento–bregmatic
9.5 cm
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MECHANISM OF DELIVERY
It is the changes in the attidude and position that the foetus
undergoes during its passage though the birth canal.
A. DELIVERY OF THE HEAD
1- Descent:
- A continuous movement throughout labor due to:
- Uterine contractions & retractions.
- Auxiliary force in the 2nd stage of labor.
- Straightening of the fetus caused by contraction & retraction of
the uterus.
2- Engagement:
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Is the passage of the widest transverse diameter of the
presenting part through the plane of the pelvic inlet. In cephalic
presentation it is the passage of the biparietal diameter
through the plane of the pelvic brim.
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3- Increased flexion:
When the head meets resistance during its descent, the force applied
on the sinciput is greater than that on the occiput leading to increased
flexion.
It is explained by the two armed lever theory, where the head is
represented by two armes of unequal lengths:
- A short arm : extends from the occiput to the atlanto-occipital joint .
- A long arm : extends from the sinciput to the atlanto-occipital joint.
Results of increased flexion:
- The head enters the pelvis with the smallest suboccipito-bregmatic
diameter (9.5 cm.)
- The occiput meets the pelvic floor first preparatory to internal
rotation.
- The part of the head occupying the plane of the greatest
dimensions is like a circle, as the biparietal & suboccipito-bregmatic
diameters are both equal (9.5 cm). This will facilitate internal rotation
of the head .
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4- Internal rotation:
This means anterior rotation of the occiput 1/8th of a circle
(45°) as it meets the pelvic floor first.
It occurs at the level of the plane of the greatest pelvic
dimensions
Internal rotation is explained by:
-Direction of the forward sloping gutter of the levator
ani muscles. The direction of the gutter is downwards
forwards and medially.
-Rifling action of the pelvis : The largest available
diameter at the inlet is the oblique, while at the outlet is the
antero-posterior diameter.
90%of cases of occipitoposterior rotate 3/8th of a circle to
become occipito-anterior. These cases will be delivered as in
occipito-anterior.
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5- Extension:
The suboccipital region hinges under the symphysis
pubis.
The head is acted upon by 2 forces at this level in the
pelvis :Downward & forward force of the uterine
contractions ,Upward & forward force of the pelvic floor.
The net result is passage of the head forward i.e.
extension.
6- Restitution:
The occiput rotates 1/8th of a circle in an opposite
direction to internal rotation, to undo the twist of the neck
caused by internal rotation .
7- External rotation:
Rotation of the occiput 1/8th of a circle in same direction
as restitution. It is due to internal rotation of the anterior
shoulder, 1/8th of a circle from the oblique to the
anteroposterior to the posterior diameter
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B. DELIVERY OF THE SHOULDERS AND BODY
- The anterior shoulder hinges below the symphysis.
- The posterior shoulder is delivered first by lateral flexion
of the spine.
- The anterior shoulder then follows, then the rest of the
body.
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Cardinal Movements of Normal Delivery
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FRIEDMANNS CURVE
Progress in labour
CERVICAL CHANGES
CERVICAL CHANGES
Engagement and descent
Fetal head descends
through the birth canal
Defined relative to the
ischial spinIsssssches
0 station = top of head at
the spines (fully engaged)
+2 station = 2 cm past
(below) the ischial spines
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Abdominal examination
Vertex, breech or transverse lie •
Palpate vaginally •
Leopold’s Maneuvers •
Monitoring of fetal heart
MANAGEMENT OF LABOUR
Initial Assessment
History
Onset of labour pains and their quality.
Presence of show & escape of liquor.
In case of ROM: its colour and amount.
Presence and pattern of foetal movement.
General Examination
Pulse, Blood pressure, and Temperature
Degree of anxiety.
Degree of dehydration
Observation of height and weight.
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Abdominal examination
Frequency, duration and intensity of
uterine contraction
To determine the lie, presentation and
position.
Engagement of the presenting part
F.H.S. (site, rate, rhythm)
The foetal heart sounds should be checked
especially at the end of a contraction and
immediately thereafter, to identify
pathological slowing of the heart rate.
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Vaginal examination:
- To
exclude contracted pelvis.
- To assess dilatation and effacement of the cervix.
- To determine foetal presenting part (presentation,
Position, and degree of flexion).
- To detect condition of membranes and if ruptures
the presence or absence of meconium.
- Presence of prolapse of the cord.
Station of the presenting part: When the lowest
part of the fetal head is felt at the level of the ischial
spines, this is called zero station. Station + 1, +2 &
+3, means that the lowest part of the head is 1,2 or 3
cm lower than the ischial spines. Station -1, -2 & -3,
means the lowest part of the head is 1,2 or 3 cm
higher than the ischial spines.
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Frequency of vaginal examination:
This depends on the obstetrician, but at
least it is done twice;
- At the start of labor.
- If rupture of membranes occurs to
exclude cord prolapse.
Electronic FHR monitoring: (CST):
Done during and inbetween uterine
contractions whenever indicated.
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MANAGEMENT OF THE 1ST STAGE OF LABOR
1.Preparation
Antisepsis :The vulva is shaved & cleaned with an
antiseptic.
Evacuation of the bladder & rectum:
This is done to prevent reflex uterine inertia.
The bladder is evacuated by frequent
micturition or by a
catheter.
The rectum is evacuated by an enema, which
also prevents contamination .
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2. Observation:
For the mother, fetus, and progress of labour
a. The mother :for
- Pulse, blood pressure, temperature and respiratory rate.
- Uterine contractions:
§ Contractions are observed for frequency, strength and duration;
§ By the palm of the hand applied on the abdomen.
§ By a toco-dynamometer i.e. a device applied on the abdomen.
- Cervical dilatation.
- Descent of the fetus i.e. pelvic station.
- Rupture of membranes.
b. Fetal heart sounds (FHS):
- Normally the FHS are regular with a rate of 120-160 beats / minute.
- The aim of auscultating the FHS is to detect fetal distress e.g.
bradycardia .
- Methods of detection of the FHS:
§ Intermittent by the sonicaid or Pinard stethoscope every 30 minutes.
§ Continuous electronic monitoring is indicated in high-risk cases.
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3. Nutrition:
- Early in labor i.e. in the latent phase, oral sugary fluids are
given.
- In the active phase, oral feeding is avoided, as delayed gastric
emptying may lead to vomiting & aspiration if general
anesthesia is needed at any time "Mendelson syndrome"
- If labor is prolonged more than 8 hours, IV fluids as glucose
5% and saline are given.
4. Pain relief:
- Pethidine 50 mg IM is commonly used.
Pethidine causes fetal respiratory depression & should be
stopped 2 hours before the 2nd stage of labor, to avoid fetal
respiratory depression at birth .
- Epidural analgesia is an alternative.
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5. Instructions:
- If the membranes are ruptured: Rest in bed in the lateral
position.
- If the membranes are intact:
- Walking is allowed in between uterine contractions.
-Straining (bearing down) should be avoided because:
§ It is useless & exhausts the patient.
§ It predisposes to genital prolapse.
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”Partogram“
This is a graphic record of labour which allows an instant
visual assessment of the rate of cervical dilatation against an
expected norm according to parity of the women so that active
management can be instituted immediately. Other
observations can be recorded on the chart as the frequency
and strength of contractions the descent of the head, timing of
rupture membranes, medications given and the basic
observations as the blood pressure, pulse rate and
temperature.
Figure for partogram
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MANAGEMENT OF THE 2ND STAGE OF LABOR
Identification of the 2nd stage:
1- Full dilatation of the cervix (10 cm or 5 fingers): The most
sure sign.
2- Desire of the patient to evacuate the rectum.
3- Reflex desire to bear down.
4- Bearing down is accompanied by an expiratory grunt.
5- Rupture of membranes:
- In 1st stage ,the amniotic sac is divided by contact of the
head and cervix into (A): The bag of hind-waters( B :)The
bag of fore-waters i.e. the head forms a ball valve
mechanism between both bags .
- After full cervical dilatation ,The hind & fore-waters become
continuous leading to increased pressure in the fore-waters
& rupture of membranes.
- It should be noted that rupture of membranes may occur
early before the 2nd stage of labor.
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CONDUCT OF LABOR:
1- Preparation :
- Delivery is carried out in the delivery room or operation theater.
- The patient is put in the Lithotomy or dorsal position.
- The vulva & perineum are washed by an antiseptic from before
backward.
- Sterile towels are applied on the patient.
2- Instructions :The patient is instructed to strain during contractions
& to relax in between.
3- Delivery of the head and prevention of perineal tears:
Crowning:
- It is passage of the biparietal diameter through the vulval ring.
- It is identified when the head does not recede in between
contractions.
- After crowning, extension of the head will distend the vulva by the
suboccipito-frontal diameter (10 cm.)
- Before crowning, extension of the head will over-distend the vulva by
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the occipito-frontal diameter (11.5
cm)
with liability to perineal tears.
a. Perineal support:
- It is done by a sterile dressing when the head appears at the
vulva.
- It is done to prevent extension of the head before crowning.
b. Delivery of the head should be:
- Slow, in between uterine contractions & without bearing down.
-Aided by Ritgen maneuver, which is controlled extension of the
head
c. Episiotomy :
- Episiotomy is a perineal incision during labor to prevent perineal
tears.
-Timing: It is done when the head maximally distends the vulva .
(See Episiotomy in Obstetric Operations)
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Restrictive use of episiotomy
4- After delivery of the head:
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Clearance of the air passages by swabbing & aspiration.
Coils of the umbilical cord around the fetal neck:
One loop is slipped.
Several loops are doubly clamped & the cord is cut in between.
Delivery of the shoulders & body:
Gentle downward traction on the head is done till the anterior
shoulder appears under the symphysis pubis.
The head is then lifted upward to deliver the posterior shoulder
first.
The head is then depressed downwards to deliver the anterior
shoulder.
Handling of the fetus:
After delivery, the fetus is held from its ankles.
Lifting the fetus from the ankles is avoided if:
a. Asphyxia or suspicion of intracranial hemorrhage.
b. Preterm fetuses.
• The umbilical cord is cut between 2 clamps
• Milking the cord, should not be done in
• Rh incompatibility, to avoid bringing more antibodies
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MANAGEMENT OF THE 3RD STAGE OF LABOR
Duration: 5-10 minutes, if more than 30 minutes it is considered
a prolonged 3rd stage.
A. Conservative method :
1- Exclusion of bleeding & uterine atony:
-The ulnar border of the left hand is put on the fundus
-A rise of the fundal level of a lax uterus points to bleeding inside
the uterus, but avoiding massage or kneading.
2- Signs of separation of the placenta are awaited:
-The body of the uterus becomes smaller, harder & globular.
-Suprapubic bulge due to presence of the placenta in the lower
uterine segment
-Elongation of the cord without receding.
-Gush of blood from the vagina due to expulsion of the
retroplacental clot.
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3 .Uterine massage:
Allows contraction of the uterus and controls bleeding.
4 .Placental expulsion:
This is done by asking the patient to bear down or by
fundal pressure. Fundal pressure is avoided if the uterus
is lax, to avoid inversion of the uterus .
5 .Uterine stimulants:
- To prevent atonic postpartum hemorrhage;
- Ergometrine 0.25 mg IM or oxytocin 5 units IV drip are
given.
Disadvantages:
- Takes longer time
- Risk of postpartum hemorrhage is 5%
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B. Active method "Modern management :"
1. Uterine stimulants:
With delivery of the anterior shoulder, ergometrine 0.25 - 0.5
mg IV is given, to
produce strong uterine contractions &
thus rapid placental separation .
2. Brandt-Andrews method "Conttrolled cord traction:"
The left hand is put suprapubic & when the uterus
contracts, the uterus is pushed upwards. The other hand
exerts gentle traction on the cord.
Disadvantages of the active method:
Rupture of the cord.
Acute inversion of the uterus if done on a lax uterus.
Thus, cord traction is avoided if the uterus is lax, to
avoid inversion of the uterus.
Advantages of the active method :
Less duration & less blood loss .
Significant reduction in postpartum hemorrhage
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Controlled cord traction
-C. After placental delivery:
- The placenta is rolled by both hands, to make the
membranes like a rope, to avoid missing part of the
membranes.
- The placenta is inspected to avoid missing parts.
- Repair of perineal tears, if more than 1 cm or if bleeding.
- The vulva is washed with an antiseptic and covered by a
sterile dressing.
Blood loss in the 3rd stage of labor:
- 200-300 ml from the placental site.
- 100-200 ml from the episiotomy or perineal lacerations.
- During cesarean section, blood loss from the placental
site is up to 900 ml.
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MANAGEMENT OF THE 4TH STAGE OF LABOR
-It is the 1st hour after delivery in which postpartum hemorrhage is liable.
-Careful observation to detect postpartum hemorrhage.
-Uterine massage is done every 15 minutes.
MANAGEMENT OF THE NEWBORN
1. Warmth:
On a special heated unit with a thermal regulation.
2. Care of respiration:
-The newborn is placed supine with head lowered & turned to one side.
-Suction, of the mouth & nose by a catheter connected to a suction pump.
-If respiration is delayed, respiration is stimulated by slapping the sole or back.
-Apgar score is done for evaluation of the newborn.
3. Care of the umbilical cord stump:
-Asepsis: To avoid neonatal tetanus or infections
-It is ligated by 2 silk ligatures or plastic clamps 4 and 5 cm from the umbilicus.
-The cord is cut distal to the 2nd ligature to avoid tying an umbilical hernia.
4. Care of the eyes:
Penicillin or tetracycline drops are used to prevent infection of the eyes.
5. The weight is recorded.
6. Identification ,by an identification band or footprint of the newborn.
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7. Detection of congenital anomalies e.g.
Hypospadius or imperforate anus i.e. failure to pass
meconium in the 1st day.
8. Vitamin K administration:
To prevent hemorrhagic disease of the newborn.
9 .Physiological jaundice ,may develop after 24
hours.
Effects of labor on the fetus:
1. Moulding :
- Moulding is overlap of the bones of the skull vault,
due to compression.
- Slight moulding, helps easy passage of the head
through the pelvis.
- Marked moulding may cause intracanial hemorrhage.
2.62 Caput SuccedaneumOsman
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