A 31-year-old gravida 7, para 4 presented at 38+4 weeks gestation in spontaneous labour. The patient had four previous uncomplicated vaginal births. She had a BMI of 18 with no significant medical co-morbidities, but was a current smoker of 10 cigarettes each day. Intrauterine growth restriction was diagnosed in her last pregnancy so serial growth scans were organised in this pregnancy. Antenatal care was provided at the hospital midwifery clinic with an uneventful antenatal course.
The most recent ultrasound prior to this presentation was at 36 weeks, which showed a normally grown baby in breech presentation with one leg extended. The placenta was posterior and clear of the cervical os. Amniotic fluid index was within normal range.
On initial assessment, fundal height was in keeping with dates with the fetus in cephalic presentation and the head was engaged in the pelvis. Regular uterine contractions were palpable, 4:10 that were noted to be moderate in intensity. Vaginal examination was performed that found the cervix to be 5cm dilated, 1cm thick with a station of spines -1. Bedside ultrasound was performed to confirm cephalic presentation. CTG was normal.
The patient continued in established labour and was offered re-assessment four hours later, which she declined. The next examination was six hours from initial assessment; however, the cervix was unchanged. The patient was offered artificial rupture of membranes (AROM), which was performed by the midwife after explanation of the intervention and with her consent. Clear liquor drained then a loop of pulsating cord was palpable posteriorly.
The midwife manually elevated the presenting part and called for help, with a medical officer and two midwives arriving immediately. The mother was put into left lateral position with elevation of the hips. CTG continued; however, the fetal heart was not detected. A further attempt with Doppler was unsuccessful.
A category 1 caesarean section was called, with the theatre team, anaesthetist and paediatrics registrar notified. A live male was delivered as cephalic within 12 minutes with an Apgar score of 9 at one minute and 9 at five minutes. Birth weight was 3120g and cord gases were normal (arterial pH 7.18, BE -5, lactate 3.7; venous pH 7.24, BE-7, lactate 3.0). The baby was admitted to special care nursery with respiratory distress requiring CPAP. This was complicated by small bilateral pneumothoraces and presumed sepsis. The mother was well after delivery and received debriefing with the team involved and support from the perinatal social worker. Both mother and baby were discharged day four postpartum.
Umbilical cord prolapse occurs when the umbilical cord has descended past the presenting part following either spontaneous rupture of membranes (SROM) or AROM. A pulsatile cord may be palpable on vaginal examination or cord may even be visible in the vagina. Cord presentation refers to the umbilical cord lying over the presenting part when the membranes are intact.
Overall incidence of umbilical cord prolapse is 0.1–0.6 per cent, with a perinatal mortality rate of 91 per 1000.1 The combination of cord compression and vasospasm prevents blood flow to the fetus, causing asphyxia or death.2 Risk factors for umbilical cord prolapse include multiparity, polyhydramnios, unstable lie or breech presentation.3 Antenatal factors where the presenting part is poorly applied to the cervix increase the likelihood of cord prolapse and must be considered when planning AROM. In this case, the contributing factors are AROM and multiparity; however, unstable lie may be possible, given the finding of breech presentation on ultrasound at 36 weeks. Preterm labour is also a risk factor for cord prolapse and further contributes to the reported morbidity and mortality.
In the presence of an abnormal CTG after rupture of membranes, a vaginal examination should be performed to exclude cord prolapse. In this case, the midwife assessed the application of the head after liquor drained and in doing so detected the pulsating cord from the cervix.
Cord prolapse is an obstetric emergency and delivery must be expedited. Cord prolapse occurring before full dilatation requires emergency caesarean section. An assisted vaginal delivery can be considered if the cervix is fully dilated, depending on factors including parity, station and fetal wellbeing.
Once detected, call for help and manually elevate the presenting part off the cord. When help arrives, a team member should have the role of scribe and note the time. The woman should be moved on to all fours position, with knees to the chest or placed in the left lateral position with the hips elevated. Cord handling should be minimised to prevent cord spasm. There is no evidence to support the use of saline-soaked gauze or manually replacing the cord.4
Fetal heart rate should be monitored and urgent transfer to theatre organised, with anaesthetic team present as well as staff trained in neonatal resuscitation. In the absence of regional anaesthesia, a general anaesthetic should be used to minimise the interval to delivery.
If oxytocinon infusion is in use, it should be stopped immediately. If there is a delay in transfer to theatre, tocolysis can be considered in an effort to reduce compression on the cord; however, this should not delay definitive treatment.5
Filling the bladder with 500ml of normal saline has also been described to elevate the presenting part off the cord as well as inhibiting uterine contractions.6This can be used if there will be a delay in delivery, such as during transfer to hospital from the community setting. The elevation of the presenting part should continue until the time of delivery. Paired cord gases should be obtained at delivery.
The woman and her support people should have a timely debrief to discuss the events and address any questions or concerns there may be. This is also an opportunity to discuss mode of future deliveries and offer reassurance.
Can cord prolapse be avoided?
Women with unstable or transverse lie can be offered admission from 37 weeks. Those with high risk of cord prolapse should be admitted after rupture of membranes and delivery should be planned. Inpatient management allows for adequate monitoring and minimises delay in diagnosis and interval to delivery. Those with non-vertex presentations with preterm prelabour rupture of membranes are at significantly higher risk of cord prolapse and should be managed in the inpatient setting.7 8 Those women with known risk factors should be counselled antenatally about cord prolapse and be encouraged to present urgently if contracting or after rupture of membranes.
AROM should be avoided when the presenting part is high. If the head is poorly applied, this should only be performed when necessary and in the presence of senior medical staff and within access to emergency theatre. During vaginal examination, upward pressure on the presenting part should be avoided as this may disengage the head, predisposing to cord prolapse.
AROM must be avoided if there is uncertainty regarding vaginal examination findings. If there is concern regarding the presence of cord with membranes intact, a senior practitioner should review and proceed as appropriate. If a cord presentation is detected in labour, a caesarean section should be performed.9
Can cord presentation be detected antenatally?
The use of routine ultrasound to detect cord presentation is not recommended.10 In a study of 13 cases of cord presentation detected on third trimester ultrasound, seven women were followed up with repeat ultrasound scans. Four patients were found to have resolution of cord presentation and had uncomplicated vaginal births. Out of the remaining three patients, two had elective caesarean sections for persisting cord presentation with one requiring emergency caesarean section for cord prolapse.11 Cord presentation and cord prolapse are therefore not synonymous; however, the association is higher in non-cephalic presentations.
In a study group of 198 breech presentations after 36 completed weeks gestation, 4 per cent had cord presentation diagnosed on transvaginal ultrasound. These women were counselled and seven opted for elective caesarean section. In six of the seven cases, cord presentation was found at the time of delivery.12
In summary, women with multiple risk factors for cord prolapse should receive appropriate antenatal counselling and advised to present early if in labour or if SROM is suspected. Discussion regarding mode of delivery is also relevant in those with non-cephalic presentations or those with the incidental finding of cord presentation on third trimester ultrasound scan. In such cases, follow-up scans may be appropriate depending on gestation. Maternity staff should be trained in management of cord prolapse with regular simulation training and drills.