Normal labour

NORMAL LABOUR
Prepared by
Nirsuba Gurung
Assistant lecturer
MSON

Labour (parturition)
• It Is the process where by with time regular
uterine contractions, brings about progressive
effacment and dilatation of the cervix, resulting
in delivery of the fetus from the uterus and
expulsion of the placenta at or beyond 24 (or 28)
completed weeks of pregnancy.
It is a social, psycological and economical event for
the couple, family and community.

Labour
• It is a physiological process by which the
fetus, placenta and membrane are expelled
out through the birth canal after twenty eight
week of pregnancy
• A parturient is a women in labour
• Parturition is the process of giving birth

NORMAL LABOUR: NORMAL PHYSIOLOGY
Passenge
r
Passage
Power

Normal labour
• Normal labour is physiological process by
which the fetus ,placenta and membrane are
expelled through the birth canal after full
term pregnancy (38-42 weeks of gestation)

• Labour is called normal when it fullfill the
following criteria :
– Spontaneous onset at term
– With vertex presentation
– Without prolongation
– Natural termination with minimal aids

NORMAL LABOUR
FIRST STAGE
SECOND STAGE
THIRD STAGE
LATENT PHASE: 0-4cm
ACTIVE PHASE: 4-10cm
FULL DILATION TO EXPULSION OF FETUS
BIRTH TO EXPULSION OF PLACENTA
Expectant (physiological) vs Active (CCT +OT)

Cervical effacement
vs
cervical dilation
Cervix closed,
3 cm long
Cervix effaced,
1 cm dilated
Cervix
5 cm dilated
Cervix
fully dilated

FIRST STAGE OF LABOUR:
LATENT vs ACTIVE PHASE

• Cervical dilatation: The cervix begins
dilating and stretching beyond the normal
dimensions and is measured in centimeters.
(0-10cm).
• Cervical effacement: softening, thinning
and shortening of the cervix. It is expressed in
percentage (0 – 100%)

1. True labour pains – colicky pain in the abdomen and back are
characterized by:
charactercharacter True labour painTrue labour pain False labour painFalse labour pain
contractionscontractions regularregular IrregularIrregular
Interval betweenInterval between
contractions andcontractions and
intensityintensity
Progressive (increase inProgressive (increase in
frequency andfrequency and
intensity)intensity)
Short duration, notShort duration, not
progressiveprogressive
Changes in the cervixChanges in the cervix Associated withAssociated with
effacement and dilationeffacement and dilation
of the cervixof the cervix
Not associated withNot associated with
effacement and dilationeffacement and dilation
of the cervixof the cervix
MembranesMembranes Associated with bulging ofAssociated with bulging of
membranesmembranes
Not associated withNot associated with
bulging of membranesbulging of membranes
Response to analgesiaResponse to analgesia Not relieved by sedationNot relieved by sedation Relieved by sedationRelieved by sedation
LabourLabour Followed by labourFollowed by labour Not followed by labourNot followed by labour

passengers
• The following will pass during labour (fetus,
cord, placenta and membranes). The most
important to pass is the head and shoulder

Moulding of the skull:
• means obliteration of the suture line between the
bones and overlapping of the un-united bones of
the fetal skull, and is measured by degree.
Degree Clinical finding
+
++
+++
Suture line closed, no overlap
Overlap of suture line reducible
Overlap of suture line irreducible
As the degree of moulding increase- means there is CPD

Fetal attitude: is the relation of the fetal parts to
each other
• 1- flexion attitude (common)
• 2- extension attitude (rare).

Clinical course of labour
Onset of labour: not definitely known – however there
are several theories, but none of them is completely
proven.
Mechanical theories: - uterine distension
Hormonal theories:
1. Maternal :
o progesterone withdrawal
o oxytocin stimulation
o prostaglandins
o serotonin
2. fetal:
o fetal cortisol
o fetal membranes
3. Neuronal factors:
o sympathetic- alpha receptor stimulation

2. Show – blood stained mucous.
3. SROM
B. Signs:
o palpable or recorded uterine contraction
o effacement and dilation of the cervix
o formation of forewater

STAGES OF LABOUR:
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.
THE ACTIVE STAGE OF LABOUR – WHEN THE CERVIXTHE ACTIVE STAGE OF LABOUR – WHEN THE CERVIX
IS MORE THAN 3 CM DILATED AND FULLY EFFACEDIS MORE THAN 3 CM DILATED AND FULLY EFFACED

Duration:
o primigravida = 8-12 h
o multigravida = 6-8 h
Phases of the first stage:
 Latent phase: started when the cervix dilatated
slowly and reached to about 3cm.
A. in primigravida = 8h
B. in multigravida = 4h
 - Active phase: rapid dilatation of the cervix to reach
10cm
A. in primigravda = 4h
B. in multigravida =2h

The active phase is divided into:
1. Accelerative phase
2. Slopping phase
3. Decelerative:
A. prolonged active phase
B. primary dysfunction: dilation in active phase
of<1cm/hr
C. secondary arrest: active phase dilation stops
or slow significantly.
N.B – in primigravida the cervix dilates from
above downwards, in multigravida dilatation
of the internal os, taking up of the cervix and
dilatation of the external os occurs
simultaneously.

Factors affecting cervical dilatation:
1. Contraction and retraction of the
uterus.
2. The bag of fore-water.
3. Absence of membranes.
4. Fitting of the presenting part to the
lower segment and the cervix.
5. Pre-labour changes in the cervix (eg,
softening)

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.29-30
Duration:
A.in primigravida =1 h
B.in 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

The second stage of labour had two
phases:
1. Passive phase – stage of descent of the
presenting part and dilatation of the
vagina – due to contraction and
retraction of the uterine muscle.
2. Expulsive phase – stage of bearing down
– due to contraction and retraction of
the uterine muscle and voluntary efforts
by diaphragm and abdominal muscles.

Mechanism of labour in vertex presentation:
Definition: The spontaneous adjustments of the
fetal position and attitude to affect efficient passage of
the fetus through the pelvis, marked by progressive
descent until delivery of the fetus.
Delivery of the fetal head:
A- Descent: is a continuous movement throughout
the process of delivery, however it becomes more
rapid in the second stage of labour, it is caused by:
o-Uterine contraction and retraction.
o-bearing down effort – mainly in the second stage of
labour

In normal pelvis, the fetal head enters with the
sagittal suture in the transverse diameter (or
occasionally oblique diameter of the brim). If
the sagittal suture in between the symphysis
pubis and sacral promontory – both parietal
bones are felt vaginally at the same level – the
head is said to be (synclitic). In such case the
biparietal diameter (9.5cm) is the diameter of
engagement. However some degree of lateral
inclination of the head over the shoulder –
(Asynclitism) is present normally as the head
enters the pelvic inlet.

*If the sagittal suture lies close to the
sacrum and the anterior patietal bone
lies over the inlet (Anterior parietal bone
presentation) - Anterior asynclitism.
*If the sagittal suture lies close to the
symphysis pubis and the posterior
parietal bone lies over the inlet
(posterior parietal bone presentation) –
posterior asynclitism.

Causes of non-engagement:
 Erroneous dates (primigravida)
 Extra-uterine:
A. full bladder or loaded rectum
B. Pelvic tumours
C. Pendulous abdomen and marked lumbar lordosis.
D. High angle of inclination of the pelvis.
E. Contracted pelvis.
 -Uterine:
A. Poor uterine tone.
B. Congenital deformities.
C. Fibromyomata.
D. Placenta previa.

 -Fetal:
A. polyhydramnios.
B. Short umbilical cord(acutal or relative, due to
entanglement)
C. Large baby.
D. Deflexion attitude, and malposition.
E. Multiple pregnancy.
F. Hydrocephalus.
Engagement – can be assessed by abdominal
station in fifths during antenatal period, and
by abdominal and vaginal stations during
labour.

C.Increased flexion: as the head
descends, it meets resistance from the
pelvic walls and floor and this leads to
increased flexion of the head. As the head
flexed it brings the shortest longitudinal
diameter of the head (sub-occipito-
bregmatic – 9.5cm) to pass through the
birth canal. Flexion is explained by the
(two armed lever theory).

D-Internal rotation: the internal rotation occurs
as the head descends through the pelvic cavity.
As the head enters the pelvic inlet in transverse
diameter will rotate 3/8 of the cycle to pass
through the pelvic outlet in antero-posterior
diameter.
The rotation is favoured by the slopping shape of
the pelvic floor, angling the leading point of the
head (occiput) in downward and forward
direction, by the effect of the contraction and
retraction of the uterus.

E-Crowning, extension and delivery of the fetal head:
The combined effect of descent and internal rotation
bring the presenting diameter to the plane of the pelvic
outlet, with the occiput lying under the pubic arch and
the sinciput at the lower border of the sacrum or coccyx.
When the widest diameter of the fetal head is embraced
by the distended vulva, it is said to be crowned.
The occiput remains under the pubic arch but the
sinciput sweeps forwards as the neck extends.

The head is acted upon by:
1. The downward and forward force of the
uterine contraction and retraction.
2. The upward and forward force offered by
pelvic floor resistance so the head passes
forwards i.e. extends vertex, forehead, and
face come out successively.
Frequently, especially in primigravida, the soft
tissues are not able to distend equally so that
tearing of the perineum and adjacent tissues
may occur unless steps are taken to avoid it
by making a formal incision (episiotomy).

F-Restitution and external rotation:
Following delivery of the head the occiput rotates
to the lateral position, in the opposite direction
of internal rotation to correct the twist of the
head on the shoulders produced by internal
rotation. The internal rotation of the shoulders
inside the pelvis transmitted to the delivered
head which in turn move one eight of a circle
outside the pelvis, in the same direction as that of
the restitution, so at the end the occiput is
towards one thigh and the face is towards the
other thigh.

Delivery of the shoulder and body:
The widest diameter of the shoulders,( the bi-
acromial diameter), pass the pelvic brim at the
time when the anterior rotation of the head is
occurring. Thus the anterior rotation of the
occiput is favourable for both the head and the
shoulders. Similarly external rotation of the head
is associated with rotation of the shoulders to
bring them into the antero-posterior diameter of
the outlet. With further descent, the anterior
shoulder delivered first from under the pubic
arch, followed by posterior shoulder, during
which time lateral flexion of the trunk is
occurring. The trunk and buttocks follow with the
same or the next contraction.

Even in the course of normal delivery,
there are many variations of the
mechanisms, dependent on the variation
in the size and shape of the pelvis and of
the fetal head.
III-The Third stage of labour: the 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.
Mechanism: the third stage is made of two
phases:
1.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.

2.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:
A.-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.
B.Mattews – Duncan mechanism: (20%)
The placenta delivered side way and it
presents with it’s inferior surface first.

Stage of
labour
Definition Duration
Stage I latent
phase
(affacment)
•Begins from the onset of regular contractions.
•Ends with acceleration of cervical dilatation
•Prepares cervix for dilatation.
<20 hours in PG
<14 hours MG
Stage 1 active
phase
(dilatation)
•Begins with acceleration of cervical dilatation.
•Ends at 10 cm dilatation
•Rapid cervical dilatation
<2/hours in PG
<1.5/ hrs in MG
Stage 2
(descent)
•Begins from 10cm dilatation
•Ends with delivery of the baby
•Descent of the fetus
<2 hours in PG
<1 hours in MG
Add 1 hour in epi
Stage 3
(expulsion)
•Begins with delivery of the baby.
•Ends with delivery of the placenta
•Delivery of the placenta
<30 min.

Management of labour
The management of labour should be
commenced during the antenatal period, and
the women should be classified as high or
low risk pregnancy. The medical or surgical
problems should be corrected as in case of
(anaemia, hypertension, urinary tract
infection), vaccination should be given if
necessary, and all investigations should be
performed and prepared such as (HIV, HCV,
Hbs Ag, blood grouping…….etc).

Also the patient should be advised to attend
the antenatal class (parenterful class) and
visit the hospital including the labour ward to
be familiar to the place and staff.
Once labour is commenced and the patient
arrived to the admission room the following to
be done:

A. -Taking history or reviewing the antenatal
file.
1-Last menstrual period – expected date of
confinement.
2-Time of onset of labour.
3-Frequency and duration of contraction (3-
4cm/10min).
4-Presence or absence of amniotic fluid
leakage.
5-Presence or absence of show or vaginal
bleeding.
6-Past obstetric history especially mode of
previous delivery, presentation, mode of
delivery, and weight of previous children.
7-Past medical or surgical history that may
affect labour or delivery, especially
diabetes, heart disease, respiratory
disease allergies, and any medication.

B-Examination:
1. .General:
a-pallor, oedema, varicosities, height, and built.
b-Vital signs (BP, P, T)
c-Examination of heart, lungs, breast and other
organs if necessary
2. .Abdominal Examination:
a-To determine fundal height in cm using tape
measure (to determine gestational age
clinically), fetal lie, presentation, engagement in
fifths, size of the fetus, amount of liquor, fetal
heart rate.
b-The frequency and duration of the contraction.

3. .Vaginal Examination: to assess the following.
a-Cervical dilatation in cm and effacement in %.
b-Length of the cervix.
c-Consistency of the cervix
d-Position of the cervix
e-State of the membranes, amount and colour of
liquor.
f-fetal presentation, position and station.
g-pelvic architecture.

DO NOT DO VAGINAL EXAMINATION IN
CASES OF VAGINAL BLEEDING BEFORE
THE PLACENTA PREVIA IS EXCLUDED.
DO STERIL SPECULUM EXAMINATION IF
SUSPECTED PLROM, IF THE WOMAN IS
NOT IN LABOUR.
If the woman diagnosed as having active labour – to
be admitted to labour ward.
N.B- active labour means –regular strong and
frequent uterine contraction 3-4/10min lasting 45-50
sec, and the cervix is fully effaced and 2.5-3cm
dilated.

Arrival to the labour ward:
I-first stage of labour:
1-Ensure patient’s privacy by covering her with
sheaths or blankets.
2-Reassure and show great sympathy and interest.
3-Record maternal vital signs every hour (BP, P, T).
4-Take blood for grouping and cross match for high
risk patients.
5-Monitor:
a-high risk patients should have a continuous
electronic fetal heart monitoring.

b-low risk patients should have brief electronic fetal
heart monitoring if NORMAL, to be followed by
intermittent auscultation:
-first stage every 15min
-second stage every 5min
6-Limit oral intake to small amount of clear fluid or
frozen pineapple.
7-Give all patients in active labour Ranitidine
(Zentac) 150mg orally / 6hourly.
8-Nurse the patient in:
a-left lateral position for mediated patients.
b-sitting or semi-reclining for unmediated patients.

9-Encourage spontaneous voiding, catheterization
may be necessary.
10-Test all urine specimen for proteins, sugar, and
acetone.
11-Give IV fluids during labour to avoid
dehydration
a-0.9% Nacl or hartmann’s solution at 80-
125ml/hr
b-Supplementation with 5% dextrose to prevent
ketosis and hypoglycemia.
12-Give analgesia/anesthesia as required.
a-Pethidine (50-150mg)IM.
b-Diamorphin (5-10mg)IM. Every 3-4 hours.
*avoid giving it too early in labour < 3-4cm cervical
dilation or too late when the delivery is expected
within 1-2hours.

*if given too late:
-inform the pediatrician
-give Naloxon (Narcon) 0.02mg IM to the neonate.
c-Use Entonox (NO2 50%+O2 50%) by mask if
available.
d-Use epidural analgesia in selected cases if
available such as Breech, Twins, preterm delivery.
e-Give anti-emetics such as Metoclopromide (5-
10mg)IM if necessary, but should not be routine.
13-Do vaginal examination to:
a-assess progress of labour every 2-4hr
b-or immediately after rupture of membranes
c-FHR abnormalities.

14-Recall all the observations in labour in
Partogram.
15-Consider augmentation with syntocinon if
progress of labour is slow (partogram).
-1000 ml Hartmann’s solution or normal saline + 10
units syntocinon (pitocin)
-Begin the infusion using a pump at 4 milliunits per
minute and double the dose every 20 minutes to a
maximum of 32 milliunits/min.
-Or begin with 15 drops / min and increase the rate
by 10 drops every 30 minutes untill adequate
contractions.

II-second stage of labour:
Once the patient reach the second stage of labour and have
the desire to push down then:
1-Put the patient in lithotomy position or other positions clean
the vulva, and perineum with antiseptic solution.
2-Encourage organized pushing down which she is feeling to
do so
3. -Monitor the uterine contraction and fetal heart more
frequent.
4. -Use syntocinon if progress is slow and no contractions.
5. -When the head appears at the vulva, the perineum is
supported during uterine contraction by sterile pad to
promote flexion and prevent premature extension of the
head by pressing up on the sinciput until crowning occur.

6. -After crowning the head is allowed to be
delivered by extension slowly in between the
contractions by sliding the perineum over the
face.
7. -DO episiotomy if necessary under local
anaesthetic ( 10-20 ml) of 1% lignocain, but
should not be routine.
8. -Wait for the next contraction to deliver the
shoulder and trunks.
9. -Clamp and deliver the cord and baby to be
handled to pediatrician.

III-Third stage of labour:
The management of third stage is aimed at:
1-Complete delivery of the after birth
(placenta and membranes).
2-Prevention of acute inversion of the uterus.
3-prevention of postpartum haemorrhage

A-Delivery of the placenta and membranes:
a-Conservative method: the left hand is
placed over the abdomen to detect any
change in the level of the fundus or sign of
placental separation and decent are
detected, the patient is asked to bear down
to deliver the placenta spontaneously.
Ergometrine 0.5mg or Syntometrine(5 units
syntocinon + 0.5mg Ergometrine) to be
given intravenouslly.

Signs of separation and decent of the
placenta:
1. -The body of the uterus becomes smaller,
harder, and globular.
2. -The fundal level rises in the abdomen because
the lower segment becomes distended by the
placenta.
3. -Suprapubic bulge may appear due to presence
of the placenta in the lower segment.
4. -Elongation of the cord out side the vulva.
5. -Sudden gush of blood from the vagina.

b-Active methods(prophylaxis against postpartum
haemorrhage)
1-Give Methargine 0.5 mg IM or Syntometrine
(5units oxytocin+0.5mg Methargine), at the time
of the anterior shoulder is free from symphysis
pubis or as soon as possible thereafter.
2-Deliver the placenta and membranes by control
cord traction by right hand, and the left hand is
placed on the suprapubic region, pushing the
uterus upwards.
N.B. USE SYNTOCINON RATHER THAN
METHARGINE IN CARDIAC AND
HYPERTENSIVE CASES.

IV-Post Delivery:
1-examine the placenta for their completeness,
anomalies, length, and number of vessels in the
cord and record the placental weight.
2-Suture the episiotomy or any laceration.
3-Estimate blood loss, count swabs, and take cord
blood for Hb, blood group, Rh, bilirubin, and
coomb’s test for Rh negative mother.
4-Check BP, P, T, Lochia and firmness of the
uterus before transferring the patient.
5-Continue an infusion of syntocinon through the
first hour if necessary.
6-Allow no food during the first hour, sips of water
may be taken, encourage nursing.

V-Care of the new born infant:
1. -Clearance of the new passages.
2. -Determine the Apgar score one and five minutes
- heart rate
- respiratory rate
- muscle tone
- colour
- reflex irritability
3-Care of the umbilical cord stump
4-General assessment of the infant to exclude any
congenital anomalies.
5-Identification of weight, estimate the gestational
age, dress it and put a mask to identify it.
6-Protect the baby against cold.

A-Delivery of the fetal head:
Enter the pelvis by flexion
Engagement
Increased flexion
Internal rotation
DESCENT Crowning
Extension
Restitution
External rotation
Delivery of the fetal head
B-Delivery of the shoulder and body:

Normal labour

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