Abnormal Labour Flashcards
Consequences and management of OP position?
Larger diameter to negotiate pelvic outlet –> longer labour, more painful and earlier desire to push.
If progress is normal - no action needed. Some rotate to OA spontaneously or deliver OP.
If slow, augmentation. If no full dilation, c-section.
Consequences and management of OT position?
Occiput lies on left or right - position head normally enters the pelvis in first stage.
Rotation with traction - usually achieved with ventouse.
Consequences and management of brow position?
Extension of foetal head on neck –> large diameter (13cm) that will not deliver vaginally.
Anterior fontanelle, supraorbital ridges and nose palpable.
C-section.
Consequences and management of face presentation?
Complete extension of head –> face is presenting part (mouth eyes, nose palpable)
Can deliver if chin anterior (mento-anterior) - can be flexed over perineum. If chin posterior (MP) - c-section.
What is longitudinal lie? Two types?
Foetus lying longitudinally within the uterus
Cephalic or breech
Transverse and oblique lie?
Transverse = lying across uterus with head in flank
Oblique = lying across uterus with head in iliac fossa
Causes of abnormal lie?
Preterm labour (complicated more by abnormal lie)
More room to turn (polyhydramnios, high parity = lax uterus –> unstable lie)
Prevention of turning (foetal/uterine abnormalities, twin pregnancies)
Prevention of engagement (placenta praevia, pelvic tumours/uterine deformities)
In whom is unstable lie rare?
Nulliparous women
Potential complications of abnormal lie?
Head/breech cannot enter pelvis –> labour cannot deliver foetus
Uterine rupture as a result of prolapse of an arm or the cord when membranes rupture
Management of abnormal lie? (before 37 weeks)
No management before 37 weeks unless woman in labour
Management of abnormal lie? (after 37 weeks)
Admit to hospital in case membranes rupture - USS to exclude identifiable causes
ECV not justified - if spontaneous version occurs and persists for more than 48 hours woman can be discharged.
Abnormal lie usually stabilises before 41 weeks in absence of obstruction.
PERSISTENT ABNORMAL LIE –> c-section
What is breech presentation?
Presentation of the buttocks (3% of term pregnancies)
What are the 3 types of breech presentation and their incidences?
Extended (Frank) Breech (70%) – both legs extended at the knee.
Flexed (Complete) Breech (15%) – both legs flexed at knee.
Footling (Incomplete) Breech (15%) - more common if preterm – one or both feet present below buttocks.
Types of footling breech?
Single footling
Double footling
Footling-frank
Kneeling
Diagnosis of breech presentation?
Only important from 37 weeks or if in labour.
- Upper abdominal discomfort common
- Hard head normally palpable and ballotable at the fundus
- USS – confirms diagnosis, helps detection of foetal abnormality, pelvic tumour or placenta praevia and ensures prerequisites for ECV are met.
Complications of breech presentation?
Perinatal and long-term morbidity/mortality increased.
Labour has potential hazards
Cord prolapse, trapping of after-coming head
What is ECV?
After 37 weeks – attempt made to turn baby to cephalic position –> hopefully reduction in breech presentation at term –> no caesarean or vaginal breech delivery.
When is ECV not recommended?
Before 37 weeks!
What is the success rate of ECV? Who has lower success rates?
50% –> 3% of successfully turned breeches will turn back
Lower success in nulliparous women, Caucasians, obese women and liquor volume reduced.
Process of ECV?
Breech mobilised, manual forward rotation using both hands (one to push breech and other to guide vertex) - completion of forward roll, then backward roll.
CTG straigh after and anti-d given to resus -ve women
Risks of ECV?
Low complication rate
Pain Transient bradycardia (resolves spontaneously) Abruption (<1%) Prolonged bradycardia Emergency LSCS (0.5%).
Contraindicaitons to ECV?
Absolute = placenta praevia (vaginal birth contraindicated anyway), uterine malformations, antepartum haemorrhage, rupture membranes, abnormal CTG, multiple pregnancy.
Relative = previous CS (1 is fine), active labour, preeclampsia, oligohydramnios, foetal abnormalities, hypertension of foetal heart, maternal cardiac disease.
C-section in breech presentation?
If ECV failed or contraindicated or breech presentation missed – safest method of delivery is elective C-section.
- Reduces neonatal mortality and short-term morbidity – does not affect long-term outcomes. Maternal morbidity not increased.
- 1/3 of attempts at breech delivery end in emergency caesarean anyway – greater risks than elective.
- Decision is up to parents in the end.
Process of vaginal breech delivery?
Buttocks distend perineum, perform episiotomy.
Finger behind knee delivers legs, finger hooks each arm down, forceps deliver head once arms out.
What is most common method of delivery for twins and why?
Caesarean section increasingly used for all – even uncomplicated. Due to increased risk of death and hypoxia in second twin compared to the first.
When is c-section absolutely indicated in twin delivery?
o If first foetus is breech or transverse lie (20%)
o Triplets (or other high order multiples)
o If there have been antepartum complications
o With monochorionic twins
When would vaginal delivery be appropriate in twin delivery?
When first foetus is cephalic
Timing of induction/caesarean in twin delivery?
38 weeks (DC twins)
36-37 weeks (MC twins)
After this point perinatal mortality is increased.
Monitoring/epidural in twin delivery?
CTG advised
Epidural recommended as difficulty sometimes in delivering second twin
Process of twin delivery?
First twin delivered normally –> contractions usually diminish after first twin then return after a few minutes (oxytocin if not).
Lie of second twin checked and ECV performed if not longitudinal –> head or breech enters pelvis –> membranes ruptured (amniotomy) and pushing begins again.
Delivery usually easy whether cephalic or breech – 20 minutes after first foetus. (Delay associated with increased morbidity for second twin)
Problems in twin delivery? (2nd twin)
If head does not descend – malpresentation (usually brow) is likely –> C-section
If foetal distress/cord prolapse –> ventouse or breech extraction (GA/epidural/spinal).
Indications for instrumental deliivery?
Prolonged 2nd stage (after 1 hour)
Foetal distress
Prophylactic (avoiding labour)
Breech delivery
Pre-requisites for instrumental delivery?
- Head not be palpable abdominally (deeply engaged)
- Head at or lower than the level of ischial spines on vaginal examination
- Cervix must be fully dilated
- Position of head must be known
- Adequate analgesia
- Bladder should be empty
What is ventouse?
Consists of rubber or metal cap, connected to handle. Cap fixed near foetal occiput by suction. Traction during maternal pushing will delvier OA head; also allows shape of pelvis to simultaneously rotate a malpositioned head to OA position.
Examples of non-rotational forceps?
Simpson’s
Neville-Barnes
When can non-rotational forceps be used? What is their shape?
Grip head in whatever position it is in to allow traction. Only suitable when occiput is anterior.
Have a ‘cephalic’ curve for the head and a ‘pelvic curve’ which follows the sacral curve.
Example of rotational forceps?
Kielland’s
Use for rotaional forceps? Shape?
Have no pelvic curve and enable a malpositioned head to be rotated by the operator in the OA position, before traction is applied.
Forceps vs Ventouse?
Ventouse causes…
- Higher failure rate (but LSCS not more common if forceps then used)
- More foetal trauma
- No difference in Apgar scores
- Less maternal trauma.
What is the thing on the baby’s head called after ventouse?
Chignon
What % of deliveries are C-sections?
20-30%
What kind of incision in C-section?
Suprapubic transverse incision
Indications for emergency c-section?
Failure to progress (prolonged first stage)
Foetal distress
Indications for elective c-section
Absolute = placenta praevia, severe antenatal foetal compromise, uncorrectable abnormal lie, previous vertical C-section, gross pelvic deformity
Relative = breech, twins, DM/others, previous C-section, older nulliparous patients
When delivery needed before 34 weeks
Maternal request for c-section?
Should try to understand and address the reasons for the request, and encourage normal birth. If not, most obstetricians now agree to procedure.
Complications of c-section? (maternal)
Rare but greater than vaginal delivery (more common with emergency)
Haemorrhage Infection Bladder/bowel damage Post-operative pain/immobility VTE
Foetal complications of c-section?
Elective c-section increases risk of respiratory mortality at any given gestational age. Should not be done before 39 weeks if uncomplicated.
Complications for subsequent pregnancies with c-section?
Incidence of placenta praevia is more common in pregnancies after a caesarean.
Placenta accreta/percreta
Placenta may implant more deeply than normal, into myometrium (accrete) or through into surrounding structures (percreta).
Can need hysterectomy and can be lethal.
What is shoulder dystocia?
When additional manoeuvres required after normal downward traction has failed to deliver the shoulders after the head is delivered – 1 in 200 deliveries.
Potential consequence of shoulder dystocia
Excessive traction on the neck damages the brachial plexus –> Erb’s (waiter’s tip) palsy.
Delay in delivery can be lethal
Risk factors for shoulder dystocia?
- Large baby – but only half of all cases occur in babies >4kg – also antenatal prediction of foetal size is poor.
- Maternal BMI
- Labour induction
- Low height
- Maternal DM
- Instrumental delivery
External manoeuvres in shoulder dystocia?
Gentle downward traction - Because obstruction is at pelvic inlet, excessive traction is useless –> Erb’s palsy
McRoberts’ manoeuvre - Legs are hyperextended onto the abdomen. Suprapubic pressure also applied. Facilitates disimpaction of anterior foetal shoulder.
Internal manouvres in shoulder dystocia?
• Wood’s screw manoeuvre - Insert two fingers into the vagina posteriorly and apply pressure to the anterior surface of the posterior shoulder to rotate the infant 180°
Delivery of Posterior Arm - Posterior arm grasped and, by extension at elbow, hand is brought down and swept across foetal chest.
What may result from delivery of posterior arm?
Fracture of clavicle and/or humerus may result
Last resorts in shoulder dystocia?
Symphysiotomy - cartilage of the pubic symphysis is divided to widen the pelvis
Zanavelli Manoeuvre - Replacement of the head (rotated to OA position, flexed rotated and pushed back up to uterus) and caesarean section.
Mnemonic for shoulder dystocia?
HELPER
- Help: Obstetrics, neonatology, anesthesia
- Episiotomy: Generous, possibly even episioproctotomy
- Legs flexed: McRoberts’ maneuver
- Pressure: Suprapubic pressure, shoulder pressure
- Enter vagina: Rubin’s maneuver or Wood’s Maneuver
- Remove posterior arm: Splint, sweep, grasp and pull to extension
