Module 6: Malpositions, malpresentations, disordered uterine action and pain in labour

Question 1

Labour dystocia: Definition and incidence

Answer 1

Definition: an abnormal or difficult labour.
Incidence: 8-11% of deliveries and the lead cause of LSCS

Question 2

Labour dystocia: cause

Answer 2

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

Question 3

When is labour dystocia suspected

Answer 3

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”

Question 4

What is inefficient uterine action

Answer 4

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.

Question 5

What is hypotonic uterine action

Answer 5

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

Question 6

Management of inefficient uterine action

Answer 6

Labour progression is currently measured against the Friedman curve, based on 100 women in 1954.
Wide variation in duration for multips and primips

Question 7

Incoordinate uterine action

Answer 7

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

Question 8

Management of incoordinate uterine action

Answer 8

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?

Question 9

Hypertonic uterine action

Answer 9

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

Question 10

Management of hypertonic uterine action

Answer 10

Determine the cause
Early recognition
Timely preparation for birth under controlled conditions
Properly administered analgesia

Question 11

Cervical dystocia

Answer 11

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.

Question 12

Pelvic dystocia

Answer 12

Contractures of the pelvic diameters reducing capacity of the inlet, cavity and the outlet.

Most common cause of obstructed labour leading to LSCS

Question 13

Soft tissue dystocia

Answer 13

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

Question 14

Fetal cause of labour dystocia

Answer 14

Anomalies eg hydrocephalus, conjoined twins
Disproportion
Malposition
Malpresentation

Question 15

Define malpositions

Answer 15

Refers to a position of the fetus in the uterus which will not aid normal progress in labour

Question 16

Define malpresentations

Answer 16

When the fetal head is not over the cervix, the breech brown, shoulder or face may be found instead.

Question 17

Brow presentation: Definition and incidence

Answer 17

Head is partly extended with the brow presenting. The forehead (glabella) is the presenting part.

Incidence 1:1500

Presenting diameter: 13.5cm - requires LSCS

Question 18

Brow presentation causes

Answer 18

Multiparity, placenta previa, uterine anomaly, polyhydramnios, prematurity, multiple births and macrosomia.

Question 19

Face presentation

Answer 19

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

Question 20

Shoulder presentation: Cause and management

Answer 20

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.

Question 21

Breech presentation: Definition and incidence

Answer 21

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

Question 22

Breech presentation diagnosis

Answer 22

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

Question 23

Types of breech presentation

Answer 23

Complete (flexed)
Extended (frank)
Knee
Footling

Question 24

Causes of breech presentation

Answer 24

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.

Question 25

Breech presentation ECV

Answer 25

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

Question 26

ECV risks

Answer 26

placental abruption failed version cord entanglement ruptured uterus

Question 27

Contraindications for ECV

Answer 27

Uterine scar Hypertension Oligohydramnios H/O premature labour Multiple pregnancy Hydrocephalic fetus

Question 28

Mechanism of left sacro-anterior breech position

Answer 28

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

Question 29

Breech presentation labour management

Answer 29

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

Question 30

Breech manoeuvres

Answer 30

Mauriceau-Smellie-Veit = for jaw flexion and shoulder traction Lovet manoeuvre = for delivery of extended arms Burns Marshall method for the after coming head

Question 31

Breech presentation risks

Answer 31

Impacted breech Cord prolapse Birth injury Fetal hypoxia Premature separation of the placenta Maternal trauma

Question 32

Induction

Answer 32

Is any attempt to initiate uterine contractions before their spontaneous onset to facilitate a vaginal birth.

Question 33

Augmentation

Answer 33

Any attempt to stimulate uterine contractions during the course of labour to facilitate a vaginal birth.

Question 34

Incidence of induction/augmentation

Answer 34

35.6% of all NSW confinements were induced or augmented with ARM, oxytocin and/or prostaglandins in 2020

Question 35

Criteria to commence an induction

Answer 35

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

Question 36

Methods of induction

Answer 36

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

Question 37

Bishop's score

Answer 37

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

Question 38

Amniotomy/ARM

Answer 38

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.

Question 39

Prostaglandins

Answer 39

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

Question 40

Prostaglandins advantages and risks

Answer 40

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

Question 41

Mechanical cervical ripening

Answer 41

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

Question 42

Syntocinon

Answer 42

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

Question 43

Syntocinon side effects

Answer 43

Uterine hyperstimulation Antidiuretic effect Prematurity Fetal hypoxia Hyperbilirubinemia

Question 44

Occipito-posterior position in labour incidence and cause

Answer 44

10-25% during the early stage, 10% during the active phase and 6% at birth. More common in nulliparas. Causes pelvis type - android

Question 45

Issues with occipito-posterior position in labour

Answer 45

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.

Question 46

Labour care of women with posterior babies

Answer 46

Explanation, support Discomfort management, positions, water Nutrition Observations ? Augmentation Premature urge to push Confirmation of second stage