Flashcards in Obstetric Emergencies Deck (6)
What is cord prolapse?
Cord descends through cervix with (or before) presenting part of fetus. 0.1-0.6% of births but high mortality (~91 in 1000, as occurs more frequently in preterm babies [often breech and may have other congenital anomalies]). Occurs in presence of ruptured membranes.
• Occult (incomplete): cord descends alongside the presenting part, but not beyond it.
• Overt (complete): umbilical cord descends past presenting part and lower than the presenting part in the pelvis.
• Cord presentation: presence of umbilical cord between the presenting part and the cervix. This can occur with or without intact membranes.
Fetal hypoxia via 2 main mechanisms: occlusion (presenting part presses onto cord) + arterial vasospasm (exposure to cold atmosphere: umbilical arterial vasospasm, reducing blood flow to the fetus).
Risk factors for cord prolapse?
Unstable lie (changes between transverse/oblique/breech), Artificial rupture of membranes (particularly when presenting part of fetus is high in pelvis)
If >37 weeks and unstable lie, consider inpatient admission until delivery due to risk of cord prolapse
Diagnosis and management of cord prolapse?
Cord prolapse should always be considered if non-reassuring fetal heart beat + absent membranes. Can be confirmed by external inspection or digital vaginal examination. Fetal heart rate pattern can vary from subtle changes (e.g. decelerations with some of the contractions) to more obvious signs of fetal distress e.g. fetal bradycardia. Fetal bradycardia is strongly associated with cord prolapse (relating to the mechanism of occlusion of the cord by the presenting part). PV bleeding or heavily blood-stained liquor with ruptured membranes would suggest placental abruption or vasa praevia.
1. Call for help (obstetric emergency!)
2. Avoid handling cord to reduce vasospasm
3. Manually elevate presenting part by lifting off the cord (vaginal digital examination). If in community: fill bladder 500ml normal saline (warmed if possible) via urinary catheter & arrange immediate hospital transfer
4. Encourage into left lateral position with head down & pillow placed under left hip OR knee-chest position: relieves pressure off the cord from the presenting part.
5. Consider tocolysis (e.g. terbutaline): if delivery not imminently available, will relax uterus & stop contractions, relieving pressure from the cord. Particularly useful if there are fetal heart rate abnormalities while preparing for C-section: may also allow time for transfer to a location where delivery is feasible (e.g. operating theatre for C-section).
6. Delivery usually via emergency C-section (if fully dilated and vaginal delivery seems imminent, encourage pushing or consider instrumental delivery). If at threshold for viability (23+0 – 24+6 weeks) & extreme prematurity, expectant management may be discussed due to significant maternal morbidity with C-section at this gestation & poor fetal outcomes.
What is shoulder dystocia?
0.6-0.7% of all deliveries. After delivery of the head, anterior shoulder of fetus impacted on pubic symphysis, or less commonly, posterior shoulder becomes impacted on the sacral promontory. Defined by delay in delivery of the shoulders following the head with the next contraction after using normal traction. Leads to hypoxia in the fetus, proportional to the time delay to complete delivery.
Complications: 3rd or 4th degree tears (3-4%), PPH (11%), fetal humerus/clavicle fracture, fetal brachial plexus injury (2-16%), HIE.
Signs of shoulder dystocia?
Signs: difficulty in delivery of fetal head or chin, failure of restitution (head remains in OA position after delivery by extension), turtle neck sign (fetal head retracts slightly back into pelvis, so that the neck is no longer visible, akin to a turtle retreated into its shell.
1.. Call for help (senior obstetrician, senior midwife + paediatrician needed)
2. Advise to stop pushing (can worsen impaction)! Avoid downward traction on fetal head (increases risk of brachial plexus injury – major cause for litigation): use only routine axial traction (keep head in line with spine) and do not apply fundal pressure (increases risk of uterine rupture).
• Consider episiotomy: won’t relieve obstruction but improve access for manoeuvres
First line manoeuvres: McRoberts manœuvre +/- suprapubic pressure (>90% success)
Second line (internal manoeuvres): Posterior arm, Internal rotation (Corkscrew)
- If fail – roll onto all fours and repeat (may widen pelvic outlet).
- Additional manoeuvres (cleidotomy, symphsiotomy, Zavenelli) very rarely used in UK