Module 6: Malpositions, malpresentations, disordered uterine action and pain in labour Flashcards
Labour dystocia: Definition and incidence
Definition: an abnormal or difficult labour.
Incidence: 8-11% of deliveries and the lead cause of LSCS
Labour dystocia: cause
Three P
Powers: ineffective pattern of contractions
Passage: pelvis eg CPD
Passenger: malposition/malpresentation of the fetus
Other causes: dehydration and ketosis, psychologic state - anxiety and fear
When is labour dystocia suspected
Lack of progress in the rate of cervical dilation
Lack of progress in fetal descent and expulsion
An alteration in the characteristics of uterine contractions
Most common cause of labour dystocia will be “abnormal uterine action”
What is inefficient uterine action
Contractions do not effectively dilate the cervix
Progress in labour is slow
Length of labour is prolonged
Contractions may be too weak or not working in harmony.
What is hypotonic uterine action
Contractions are weak, short and inefficient
Slow or no cervical dilation
Woman and fetus not distressed
Either:
Primary - occurring in early labour
Secondary - after a normal contraction pattern has established
Management of inefficient uterine action
Labour progression is currently measured against the Friedman curve, based on 100 women in 1954.
Wide variation in duration for multips and primips
Incoordinate uterine action
Polarity of uterus is reversed
Cervix dilates slowly despite frequent painful contractions
Linked to malposition of the occiput.
Two types:
Colicky uterus
Hypertonic lower uterine segment
Management of incoordinate uterine action
Identify cause and correct it if possible
Emotional support
Avoid dehydration and ketosis
Ensure bladder care
Incoordinate uterine activity may be aggravated by the supine position, encourage ambulating, positions using gravity or warm bath
Augmentation with synto?
Hypertonic uterine action
Rarely occurs without the use of oxytocic’s
Pain out of proportion to contractions and cervical dilation
Seen in multiparous women with precipitate labour <2 hours.
May result in uterine rupture, perineal trauma and PPH
Outcome: dependent on risks
Management of hypertonic uterine action
Determine the cause
Early recognition
Timely preparation for birth under controlled conditions
Properly administered analgesia
Cervical dystocia
Oedematous anterior lip of cervix
Rigid cervix: uterus contracts normally but the cervix fails to dilate. Women may have a history of cervical stenosis from previous cervical surgery or congenital abnormality of the cervix
Important to exclude this prior to the use of syntocinon because of the associated risk of uterine rupture.
Pelvic dystocia
Contractures of the pelvic diameters reducing capacity of the inlet, cavity and the outlet.
Most common cause of obstructed labour leading to LSCS
Soft tissue dystocia
Obstruction of the birth passage by an anatomic abnormality other than the bony pelvis
Causes
Pelvic mass - fibroids
Ovarian tumours or rare tumours of the bony pelvis
Fetal cause of labour dystocia
Anomalies eg hydrocephalus, conjoined twins
Disproportion
Malposition
Malpresentation
Define malpositions
Refers to a position of the fetus in the uterus which will not aid normal progress in labour
Define malpresentations
When the fetal head is not over the cervix, the breech brown, shoulder or face may be found instead.
Brow presentation: Definition and incidence
Head is partly extended with the brow presenting. The forehead (glabella) is the presenting part.
Incidence 1:1500
Presenting diameter: 13.5cm - requires LSCS
Brow presentation causes
Multiparity, placenta previa, uterine anomaly, polyhydramnios, prematurity, multiple births and macrosomia.
Face presentation
Attitude of head is complete extension, glabella to under surface of chin lies over os.
Incidence 1:5-600 births
Considerations: Prolonged labour, escalate, avoid FSE, monitor progress
Shoulder presentation: Cause and management
Associated with transverse or oblique lie. Rare
Causes: lax multiparous uterus, placenta previa, fetal anomaly, polyhydramnios and uterine malformation
Management: usually LSCS, occasionally cephalic version is attempted but not in labour and need to exclude placenta previa.
Breech presentation: Definition and incidence
A breech presentation occurs when the buttocks lie lowermost in the maternal uterus and the fetal head occupies the fundus
Incidence: 3-4% at term and the most common malpresentation. Proportion decreases with advanced gestational age
Breech presentation diagnosis
Palpation in late pregnancy or during labour.
Auscultation of the FHR is usually heard above the umbilicus when the breech has not engaged
U/S
Fetal abnormalities in 9% of term breech births
Types of breech presentation
Complete (flexed)
Extended (frank)
Knee
Footling
Causes of breech presentation
Restricted space: primip, bicornuate uterus, fibroids, placenta previa, contracted pelvic, multiple pregnancy
Excessive uterine space: grand multiparity, polyhydramnios
Fetal causes: hydrocephaly, preterm labour, congenital anomalies.
Breech presentation ECV
External cephalic version involves turning of the breech by abdominal or intrauterine manipulation. It is recommended that all women with an uncomplicated breech bet offered an ECV between 37 and 42 weeks of pregnancy
ECV risks
placental abruption
failed version
cord entanglement
ruptured uterus
Contraindications for ECV
Uterine scar
Hypertension
Oligohydramnios
H/O premature labour
Multiple pregnancy
Hydrocephalic fetus
Mechanism of left sacro-anterior breech position
The lie is longitudinal
The attidue is one of complete flexion
The presentation is breech
The position is left sacroanterior
The denominator is the sacrum
The presenting part is the anterior buttock
The bitrochanteric diameter, 10cm, enters the pelvis in the left oblique diameter of the brim
The sacrum points to the left of the iliopectineal eminence
Compaction
Internal rotation of the buttocks
Internal rotation of the shoulders
Internal rotation of the head
External rotation of the body
Birth of the head
Breech presentation labour management
First stage: Normal labour cares, FHR assessment, membranes, liquor, pain relief. Often intrapartum monitoring and use of EDB to prevent premature pushing
Second stage: Confirm full dilatation. Notify obstetrician, pediatrician and anesthetist. No active pushing until the buttocks distends the vulva. Birth position
Third stage: timing of oxytocic
Breech manoeuvres
Mauriceau-Smellie-Veit = for jaw flexion and shoulder traction
Lovet manoeuvre = for delivery of extended arms
Burns Marshall method for the after coming head
Breech presentation risks
Impacted breech
Cord prolapse
Birth injury
Fetal hypoxia
Premature separation of the placenta
Maternal trauma
Induction
Is any attempt to initiate uterine contractions before their spontaneous onset to facilitate a vaginal birth.
Augmentation
Any attempt to stimulate uterine contractions during the course of labour to facilitate a vaginal birth.
Incidence of induction/augmentation
35.6% of all NSW confinements were induced or augmented with ARM, oxytocin and/or prostaglandins in 2020
Criteria to commence an induction
An engaged presenting part
No previous classic uterine incision
No fetopelvic disproportion
No non-reassuring fetal heart rate patterns
No major bleeding from an abruptio placenta
No placenta praevia or vasa praevia
No active herpes or primary herpes infection
Methods of induction
Oxytocin
Prostaglandins
Amniotomy/ARM
Digital stretching of the cervix
Mechanical cervical dilators
Herbs, blue and black chosh tinctures, raspberry leaf tea
Cod liver oil
Acupuncture, homeopathy
Nipple stimulation, sexual intercourse
Bishop’s score
A score is ascertained by performing a vaginal examination and assigning points to dilation, consistency, length, position and station. <6 requires cervical ripening. >9 indicates induction favourability
Amniotomy/ARM
Artificial rupture of the membranes with an amnihook.
Advantages: Decreases the length of some labours, allows assessment of the colour of the amniotic fluid, allows for internal fetal and uterine monitoring.
Risks: Can increase pain and lead to further intervention, variable decelerations, cord prolapse, vasa previa, infection.
Prostaglandins
Route: Intravaginal (posterior fornix)
Dosage: 1-2 mg can be repeated 6 hourly, max 3 doses
Care: check dates, note bishops score, explain procedure, manage anxiety, abdominal palpation, pre and post CTG, woman to remain supine for 30-60 min post administration, assess for hyperstimulation, observe other side effects
Prostaglandins advantages and risks
Advantages:
Enhanced cervical ripening
Decreased use of oxytocin
Decreased oxytocin induction time
Reduced amount of oxytocin used
Decreased caesarean section rate
Risks:
Uterine hyperstimulation - uterine rupture
Non reassuring FHR pattern changes
Gastrointestinal side effects
Mechanical cervical ripening
Various methods used; however, all stimulate the release of prostaglandins due to mechanical pressure
Mechanical methods include balloon catheters now back in practice, natural dilator, synthetic dilator
Risks: infection, PROM, hemorrhage
Syntocinon
Oxytocin promotes the contraction of the uterine smooth muscle, synthetic form is syntocinon
Administered when cervix is favourable.
Route IV through a pump, piggy backed to the main line, prepared in an isotonic solution eg Harmann’s
Care: Explanation, relieve anxiety, prepare infusion, check dates, peform palp, ARM, baseline obs, maintain infusion, positions, continuous CTF, usual labour cares
Syntocinon side effects
Uterine hyperstimulation
Antidiuretic effect
Prematurity
Fetal hypoxia
Hyperbilirubinemia
Occipito-posterior position in labour incidence and cause
10-25% during the early stage, 10% during the active phase and 6% at birth. More common in nulliparas.
Causes pelvis type - android
Issues with occipito-posterior position in labour
embranes: best if intact to facilitate the fetus to rotate
Contractions: often hypotonic, irregular, coupling, incoordinate
Progress: is slower, loss of fetal axis pressure, contractions are not effectively stimulated
Descent: is slow and requires flexion, fetal head is compressed in unfavourable diameters. Greater risk of tentorium cerebelli damage and the likelihood of intracranial haemorrhage.
Second stage and urge to push: is premature
Lots of back pain
Facilitating normal labour: active labour, upright positions, all fours, water.
Labour care of women with posterior babies
Explanation, support
Discomfort management, positions, water
Nutrition
Observations
? Augmentation
Premature urge to push
Confirmation of second stage
