NORMAL LABOUR.pdf

Definition
• Labour is the process by which the fetus is delivered after the 24th week of
gestation.
• The onset of labour is defined as the point when uterine contractions become
regular and cervical effacement and dilatation becomes progressive.
• In most cases, labour is characterized by:
1. Onset of uterine contractions, which increase in frequency, duration, and
strength over time.
2. Cervical effacement and dilatation.
3. Rupture of membranes with leakage of amniotic fluid.
4. Descent of the presenting part through the birth canal.
5. Birth of the baby.
6. Delivery of the placenta and membranes.

Physiology
• During pregnancy progesterone maintains uterine relaxation by
1. suppressing prostaglandin production,
2. inhibiting communication between myometrial cells
3. preventing oxytocin release.
• Prior to labour, there is a reduction in progesterone receptors.
• Increase Prostaglandin production by the chorion and the decidua, leading
to
1. increase in calcium influx into the myometrial cells
2. increases gap junction formation between individual myometrial cells,
which is necessary for coordinated uterine activity.

The uterus
• Myometrial cells of the uterus contain filaments of actin and myosin,
which interact and bring about contractions in response to an
increase in intracellular calcium.
• The result in the development of thicker, actively contracting ‘upper
segment’.
• At the same time, the lower segment of the uterus becomes thinner
and more stretched.

The cervix
• During the earlier stages of pregnancy, interactions between collagen,
fibronectin and dermatan sulphate (a proteoglycan) keep the cervix
firm and closed.
• During labour under the influence of prostaglandins, there is an
increase in proteolytic activity and a reduction in collagen and elastin
and increase in water content of the cervix.
• This causes cervical softening or ‘ripening’, effacement and dilatation.

Stages of lobour
First stage
• This describes the time from the diagnosis of labour to full dilatation
of the cervix (10 cm). The first stage of labour can be divided into two
phases.
• The ‘latent phase’ is the time between the onset of regular painful
contractions and 3–4 cm cervical dilatation. The duration of the latent
phase is usually lasts between 3 and 8 hours.
• The ‘active phase’ describes the time between the end of the latent
phase (3–4 cm dilatation) and full cervical dilatation (10 cm), usually
lasting between 2 and 6 hours,

Second stage
• This describes the time from full dilatation of the cervix to delivery of the
fetus.
• The second stage of labour may also be subdivided into two phases.
• The ‘passive phase’ describes the time between full dilatation and the
onset of involuntary expulsive contractions. There is no maternal urge to
push and the fetal head is still relatively high in the pelvis.
• The ‘active phase’ there is a maternal urge to push because the fetal head
is low, causing a reflex need to ‘bear down.
• Normally active second stage should last no longer than 2 hours in a
nulliparous woman and 1 hour in women who delivered vaginally before.

Third stage
• This is the time from delivery of the fetus until complete delivery of the
placenta and membranes.
• lasting for less than 30 minutes.
• Signs of placental separation
1. Apparent lengthening of the cord.
2. A small gush of blood from the placental bed.
3. Rising of the uterine fundus to above the umbilicus
4. Uterine contraction resulting in firm globular feel on palpation.
Fourth stage
immediate postpartum period of approximately 2 hours after delivery of the
placenta

Admission history
• Previous births and size of previous babies.
• Previous caesarean section.
• Onset, frequency, duration and perception of strength of the
contractions.
• Whether membranes have ruptured and, if so, colour and amount of
amniotic fluid lost.
• Presence of abnormal vaginal discharge or bleeding.
• Recent activity of the fetus (fetal movement).
• Medical or obstetric issues of note (e.g. diabetes, hypertension, fetal
growth restriction [FGR]).

General examination
• It is important to identify women who have a raised body mass index
(BMI), as this may complicate the management of labour. The
temperature, pulse and blood pressure must be recorded and a
sample of urine tested for protein, blood, ketones, glucose and
nitrates.

Abdominal examination
• Inspection for scars indicating previous surgery
• Determine the lie of the fetus (longitudinal, transverse or oblique)
• The nature of the presenting part (cephalic or breech).
• The degree of engagement must be determined in terms of fifths
palpable abdominally.
• Abdominal examination also includes an assessment of the
contractions.

Management of first stage of labour:
• One-to-one midwifery care should be provided.
• Obstetric and anaesthetic care should be available as required.
• Maternal and fetal wellbeing should be monitored.
• Vaginal examinations are performed 4 hourly and every 2 hours once the
active phase has been reached.
• Progress of labour is monitored using a partogram with timely intervention
if abnormal.
• Appropriate pain relief should be provided
• Ensure adequate hydration and light diet to prevent ketosis.
• If the membranes are intact, it is not necessary to rupture them if the
progress of labour is satisfactory.

Management of second stage of labour:
• Maternal Position: With the exception of avoiding the supine
position, the mother may assume any comfortable position
• Bearing Down: With each contraction, the mother should be
encouraged to hold her breath and bear down with expulsive efforts.
• Fetal Monitoring: the fetal heart rate should be monitored
continuously or evaluated every 15 minutes or 5 minutes in patients
with obstetric risk factors.
• Vaginal Examination every 30 minutes. Particular attention should be
paid to the descent and flexion of the presenting part, the extent of
internal rotation, and the development of molding or caput.

• Delivery of the Fetus
• To facilitate delivery of the fetal head, a Ritgen maneuver is
performed. The right hand, draped with a towel, exerts upward
pressure through the distended perineal body. This upward pressure,
which increases extension of the head and prevents it from slipping
back between contractions, is counteracted by downward pressure
on the occiput with the left hand. The downward pressure prevents
rapid extension of the head and allows a controlled delivery.

• Once the head is delivered, the airway is cleared of blood and
amniotic fluid using a bulb suction device.
• Suction of the nares is not performed if fetal distress or meconium-
stained liquor is present, because it may result in gasping and
aspiration of pharyngeal contents.
• After the airway has been cleared, an index finger is used to check
whether the umbilical cord encircles the neck. If so, the cord can
usually be slipped over the infant’s head.

• Following delivery of the head, the shoulders descend and rotate into
the anteroposterior diameter of the pelvis and are delivered.
• Delivery of the anterior shoulder is aided by gentle downward
traction on the externally rotated head.
• The posterior shoulder is delivered by elevating the head.
• Finally, the body is slowly extracted by traction on the shoulders.
• Delayed cord clamping is recommended for 1 to 2 minutes.
• After the cord is clamped, the newborn is given to the mother for
skin-to-skin contact.

Management of third stage
• Management of the third stage can be described as
• ‘active’ or ‘physiological’.

Active management of the third stage
1. Intramuscular injection of 10 IU oxytocin, given as the anterior
shoulder of the baby is delivered, or immediately after delivery of
the baby.
2. Early clamping and cutting of the umbilical cord.
3. Controlled cord traction

Physiological management of third stage
• where the placenta is delivered by maternal effort and no uterotonic
drugs are given to assist this process. It is associated with heavier
bleeding.
• In the event of haemorrhage (estimated blood loss >500 ml) or if the
placenta remains undelivered after 60 minutes of physiological
management, active management should be recommended.
• Finally, the vulva should be inspected for any tears or lacerations.
Minor tears do not require suturing, but tears extending into the
perineal muscles or episiotomy will require careful repair

Management of fourth stage beck
• Uterine palpation is done in this period to ascertain uterine tone.
• Perineal pads are applied, and the amount of blood on these pads
and maternal pulse and blood pressure are monitored closely for the
first several hours after delivery to identify excessive blood loss.

Reference
• Obstetrics by ten teachers 20th edition
• Beckmann and ling’s obstetrics and gynecology 8th edition
• Essentials of obstetrics and gynecology 6th edition
• Oxford handbook of obstetrics and gynecology 3rd edition

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