cOGText: Labour Flashcards
what is labour? (aka parturition)
the process where products of conception are expelled from the uterine cavity after 24 weeks gestation.
what is preterm labour?
before the commencement of the 37th week of gestation.
There is no normal duration of labour, average for a primiparous woman is ___ hours and for parous women, it is ___ hours.
1) 10 2) 5.5
T/F: Women should be informed that a standard duration of the latent first stage has not been established and can vary widely from one woman to another.
true
The duration of active first stage (from 5 cm until full cervical dilatation) usually does not extend beyond __ hours in first labours, and usually does not extend beyond __ hours in subsequent labours
1) 12 2) 10
A markedly prolonged labour is associated with increased fetal and maternal mortality and morbidity such as …?
fetal distress, PPH, pelvic floor dysfunction and fistulae.
how is ‘prolonged labour’ defined?
Clinically, there is not a specific duration, rather, it is diagnosed when cervical dilatation is <2cm in 4 hours during active labour.
Labour is a continuum and is divided into which 3 stages?
1st stage: starts with the onset of regular painful contractions and cervical changes until it reaches full dilatation and cervix is no longer palpable. 2nd stage: the duration from full dilatation to delivery of the fetus. 3rd stage: the time between delivery of the fetus and delivery of the placenta and membranes.
The first stage of labour is divided into which phases?
early latent phase: cervix becomes effaced, shortens in length and dilates up to 4cm active phase: cervix dilates from 4cm to full dilatation (10cm).
how long should the 3rd stage of labour take? (delivery of the fetus -> delivery of placenta + membranes)
occurs 5-10 minutes after delivery (is considered normal up to 30minutes)
What are the 2 different ways of managing the third stage?
active or physiological
The length of labour will vary between individuals. It is expected that the cervix will dilate ≥?cm in 4 hours during labour.
2
Inform women that, while the length of established first stage of labour varies between women:
- First labours last on average ___ hours and are unlikely to exceed __ hours
- Subsequent labours last on average __ hours and are unlikely to exceed __ hours
- 8, 18
- 5, 12
Definition of the second stage of labour?
when the cervix is fully dilated until complete expulsion of the baby.
The 2nd stage of labour (fully dilatation -> expulsion of the baby) is defined in which two stages?
- Passive 2nd stage: full dilatation prior to or in the absence of persistent (occurring with every contraction) involuntary expulsive contractions.
- Active 2nd stage: when the baby is visible; or Persistent involuntary expulsive contractions with a finding of full dilatation of the cervix or other signs of full dilatation of the cervix or Active maternal effort following confirmation of full dilatation of the cervix in the absence of expulsive contractions.
When is ‘delayed’ labour defined in a
- nulliparous
- multiparous
mother?
- when the active 2nd stage has reached 2 hours
- when the active 2nd stage has lasted 1 hour
at this point the patient should be referred to the obstetric registrar unless the birth is imminent.
The third stage of labour?
the time from the birth of the baby to the expulsion of the placenta and membranes.
What does physiological management of the 3rd stage refer to?
- Uterotonic drugs (oxytocin) are NOT used
- The cord is NOT clamped until the pulsations have ceased
- The placenta is delivered by maternal effort
What does active management of the third stage involve?
- prophylactic use of uterotonic drugs (oxytocin 10 units or syntometrine) with the birth of the anterior shoulder or immediately after the birth of the baby and before the cord stops pulsating or is clamped and cut
- Bladder emptying (catheterisation)
- Deferred clamping and cutting of the cord
- Controlled cord traction after signs of separation of the placenta.
What are the 3 classic signs to indicate separation of the placenta and membranes?
- uterus contracts, hardens and rises
- Umbilical cord lengthens permanently
- There’s a gush of blood variable in amount
- Placenta and membranes appears at introitus.
pros of active management compared to physiological management?
pros
- shortens length of 3rd stage
- is half as likely to cause N&V
cons
- higher risk of haemorrhage of >1L
- higher risk of blood transfusion
when is changing from physiological management to active management indicated?
- Excessive bleeding/ haemorrhage
- Failure to deliver the placenta within 1 hour
- patient’s desire to shorten 3rd stage
Delay in the 3rd stage is diagnosed if not completed within:
__ ___ of physiological management;
__ ___ of active management
60 minutes
30 minutes
Syntometrine is ____ in combination with ____
ergometrine
oxytocin
State 3 clinical signs of labour
- Regular, painful contractions which increase in frequency and duration and that produce progressive cervical dilatation
- The passage of blood-stained mucus from the cervix (the ‘show’) is associated with but not on its own an indicator of onset of labour.
- Rupture of membranes can be at the onset of labour but this is variable and can occur without uterine contractions.
what is
- prelabour rupture of membranes
- preterm prelabour rupture of membranes
- >4hours between ROM and onset of painful contractions
- if this occurs in the preterm period
During pregnancy, painless, irregular uterine activity is present which becomes greater with advancing gestation.
Women often experience tightenings towards the end of their gestation called ??? which are believed to be the uterine muscles preparing for labour.
Braxton Hicks contractions
Physiology of labour initiation
- Towards the end of the pregnancy, there is a downregulation of factors that keep the uterus and the cervix quiescent and an upregulation of pro-contractile influences. It involves (1) withdrawal and increases in (2) and (3) action.
- The mechanisms remain uncertain, many theories exist. One of these involves placental production of the peptide hormone (4) which increases as the placenta develops. This leads to an increase in levels of maternal and fetal plasma CRH which increases (5) and (6) synthesis and reduce (7) levels.
- (8) is released from the posterior pituitary and acts on decidual tissue to promote prostaglandin release. Oxytocin initiates and sustains (9). It is also synthesised directly in (10) and extraembryonic fetal tissues and in the (11).
- The number of (12) receptors increases in myometrial and decidual tissues near the end of pregnancy which increases uterine (13).
- These changes result in an increase in uterine myocyte (14)
- It is thought that fetal (15) release inflammatory substances that cause an inflammatory response and initiate labour.
- Another theory involves pulmonary (16), which is secreted from the foetus into amniotic fluid and is thought to stimulate prostaglandin release.
- progesterone
- oestrogen
- prostaglandin
- corticotrophin-releasing hormone (CRH)
- oestrogen
- prostaglandin
- progesterone
- Oxytocin
- contractions
- decidual
- placenta
- oxytocin
- contractility
- electrical excitability
- lungs
- surfactant
The uterine myocytes have several special features:
- They contract and shorten, and return to their precontraction length
- They contain ion channels that influence the influx of calcium ions into the myocytes and promote contraction of the myometrial cells.
- Other hormones produced in the placenta directly or indirectly influence myometrial contractility e.g. relaxin, activin A which influence production of cyclic AMP causing relaxation of myometrial cells.
The integrity of the cervix is important to retain the products of conception.
It contains myocytes and (1) and towards term, becomes soft and stretchable due to a decrease in (2) with the increase in enzyme activity.
Increased (3) reduces the affinity of fibronectin for collagen and the affinity of (4) for water causes the cervix to ripen (soften and stretch).
Progressive uterine contractions cause (5) and dilatation of the cervix as the result of (6) of myometrial fibres in the upper uterine segment and (7) of the lower uterine segment.
- fibroblasts
- collagen
- hyaluronic acid
- hyaluronic acid
- effacement
- shorting
- stretching and thinning
Reduced cervical (1) and increased (2) of uterine contraction are needed for the progress of labour.
- resistance
- frequency, duration and strength
The fetus must navigate its way through the maternal pelvis during labour as the lateral and anteroposterior diameters of the pelvis changes.
The process of normal labour therefore involves the adaptation of the fetal ____ to the various segments and diameters of the maternal pelvis described as ___ cardinal movements
head
7
describe the 7 cardinal movements of labour?
- Engagement: passage of the widest diameter of the presenting part to a level below the plane of the pelvic inlet. Is described in fifths with the proportion of the fetal head that is unpalpable used as a measure of engagement
- Descent: downward movement of the presenting part through the pelvis
- Flexion: flexion of the fetal head occurs passively as the head descends due to the shape of the bony pelvis and the resistance of soft tissues
- Internal rotation: rotation of the presenting part from its original position (usually transverse with regard to the birth canal) to the anterior position as it passes through the pelvis.
- Extension: once the fetus has reached the introitus, and the base of the occiput is in contact to the inferior margin of the pubic symphysis.
- External rotation (Restitution): return of the fetal head to the correct anatomical position in relation to the fetal torso and shoulders.
- Expulsion: delivery of the rest of fetal body
name the 7 cardinal movements of labour?
- Engagement
- Descent
- Flexion
- Internal rotation
- Extension
- Restitution (external rotation)
- Expulsion
Every Damn Fool In Egypt Eats Raw Eggs
(1) % of women will achieve a normal delivery
(2) % will not and of these, (3)% will need forceps delivery and (4)% will need a caesarean section.
- 60
- 40
- 15
- 25
T/F: generally, parous women have less operative delivery.
true
There are many situations that constitute as abnormal labour, including…?
- Malpresentation (non-vertex) inc. breech, transverse, shoulder/arm, face, brow presentations.
- Malposition (Occipitoposterior or occipitotransverse)
- Preterm labour <37 weeks
- Post-term labour >42weeks
- Too painful – requires anaesthetic input
- Too quick – hyperstimulation, precipitate labour
- Too long – failure to progress, obstruction
- Fetal distress – hypoxia and sepsis
what is the vertex?
an area of the fetal skull that is bounded by the anterior and posterior fontanelles and the parietal eminences.
90% of primigravida women deliver within ___hours, and 90% of multigravida women deliver within __ hours
16
12
There are many types of forceps depending on the station of the baby’s head and whether there’s a need to turn baby into a favourable position for birth.
Generally there are which 3 main types of forceps?
- outlet forceps (left)
- low-cavity/mid-cavity forceps (centre)
- rotational forceps (right)
Caput succedaneum
- Onset
- Pathology
- Site
- Associated features
- Time to resolve
- Management
Caput succedaneum
- Present at birth (often following a prolonged labour)
- Due to pressure of the presenting part against the cervix
- Tissue swelling forms over the vertex and crosses suture lines
- Soft puffy swelling, skin over swelling may look bruised, often with moulding.
- Days
- Conservative
Cephalohaematoma
- Onset
- Pathology
- Site
- Associated features
- Time to resolve
- Management
Cephalohaematoma
- Several hours after birth
- Subperiosteal haemorrhage due to prolonged 2nd stage or instrumental delivery
- Forms below the first layer of the periosteum. Limited by suture lines
- Jaundice in newborn, often following ventouse or forceps delivery. Swelling is firm with distinct margins. No skin discolouration. Increases in size 12-24hrs after birth
- Months
- Conservative unless hyperbilirubinaemia in neonate.
what is Chignon?
a temporary swelling after a ventouse suction cap has been used (2 hours - 2 weeks to resolve)
Subgaleal haemorrhage
- Onset
- Pathology
- Site
- Associated features
- Management
Subgaleal haemorrhage
- At delivery and may progress rapidly
- Severing of the emissary veins that are located between the dural sinuses that cover the skull and scalp.
- Forms above the periosteum, between the skull and the scalp aponeurosis. Crosses suture lines and covers a greater area than a cephalohaematoma – can involve entire cranial vault.
- Diffuse, ill-defined swelling may shift when palpated and shift with reposition of the head. Following forceps and ventouse assisted deliveries.
- Resuscitation and blood transfusions. Assess for coagulopathies
NB: Delay in recognition may lead to neonatal encephalopathy, seizures, death
Differentiating the different types of heed swelling
A bishop score of more than __ is strongly predictive of the labour following induction.
A score less than __ indicates the need for cervical ripening.
6
5
Induction of labour: stripping of the membranes
- How is this achieved?
- Hazards/ Precautions
- Finger inserted into cervix and the fetal membranes are separated from the lower segment. Requires aseptic conditions.
- Only 1/7 will labour within 48hours (high number needed to treat)
