Download Normal Labour - Department of Obstetrics and Gynecology

Labour
Prof. Mustafa Gawass FRCOG, FRCPI
objectives
Define labour.
Understand the components of labour
(passage, passenger, power).
Be able to take a focused history,
examination and anlyse the symptoms and
signs to diagnose labour.
Describe the stage sand phases of labour.
Discuss the mechanism of labour.
Discuss the management of labour.
Labour (parturition)
It Is the process where by with time regular
uterine contractions, brings about
progressive affacment 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.
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%)
A 20 year old primigravida comes to maternity
unit at 39 weeks gestation complaining of
regular uterine contractions, 3-4/10min. For the
past 6 hours. The contractions are becoming
more frequent lasting 45-50 sec. she denies
any vaginal fluid leakage. The blood pressure,
pulse and temperature are normal.
Vaginal examination cephalic, head at s-1,90%
affaced, 5 cm dilated, soft and anterior.
FH=133bpm .
What is your diagnoses?
Labour can occur at:
Term
Labour
PTL
1 LNMP
prolonged
24 W 28 W 37 W 40W 42W
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.
Components of labour:
types of female pelvis
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
Diagnosis
A.
symptoms:
1.
True labour pains – colicky pain in the abdomen and back
are characterized by:
character
True labour pain
contractions
regular
Interval between
contractions and
intensity
Changes in the cervix
Progressive (increase in
frequency and
intensity)
False labour pain
Irregular
Short duration, not
progressive
Associated with
effacement and dilation
of the cervix
Not associated with
effacement and dilation
of the cervix
Membranes
Associated with bulging of
membranes
Not associated with
bulging of membranes
Response to analgesia
Not relieved by sedation
Relieved by sedation
Labour
Followed by labour
Not followed by labour
Show – blood stained mucous.
3. SROM
2.
B. Signs:
o
o
o
palpable or recorded uterine contraction
effacement and dilation of the cervix
formation of forewater
THE ACTIVE STAGE OF LABOUR – WHEN THE CERVIX
IS MORE THAN 3 CM DILATED AND FULLY EFFACED
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.
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:


A.
B.
C.
D.
E.

A.
B.
C.
D.
Erroneous dates (primigravida)
Extra-uterine:
full bladder or loaded rectum
Pelvic tumours
Pendulous abdomen and marked lumbar lordosis.
High angle of inclination of the pelvis.
Contracted pelvis.
-Uterine:
Poor uterine tone.
Congenital deformities.
Fibromyomata.
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.
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 (suboccipito-bregmatic – 9.5cm) to pass
through the birth canal. Flexion is
explained by the (two armed lever
theory).
C. Increased
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 biacromial 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 anteroposterior 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 retroplacental 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:
-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 (34cm/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.
A.
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 4550 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 80125ml/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 (510mg)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
placenta:
and
decent
of
the
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
METHARGINE
IN
CARDIAC
HYPERTENSIVE CASES.
THAN
AND
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: