Umbilical Cord Prolapse

Question 1

Definition of umbilical cord prolapse

Answer 1

Descent of the umbilical cord through the cervix alongside (occult) or past (overt) the presenting part in the presence of rupture membranes.
Cord presentation is the presence of the umbilical cord between the foetal presenting part and the cervix, with or without intact membranes.

Question 2

Incidence and perinatal mortality rate associated with umbilcial cord prolapse

Answer 2

• Incidence ranges from 0.1-0.6% of pregnancies. However, in the case of breech presentation, the incidence is higher at 1%.
• Perinatal mortality rate has been quoted at 91 per 1000. Prematurity and congenital malformation account for the majority of adverse outcomes associated with cord prolapse (also associated with birth asphyxia)
• The principle causes of birth asphyxia are thought to be cord compression and umbilical arterial vasospasm preventing venous and arterial blood flow to and from the foetus

Question 3

Risk factors for umbilical cord prolapse

Answer 3

• General- Multiparity, low birthweight (< 2.5Kg), Preterm labour (< 37+0 weeks), foetal congenital abnormalities, breech presentation, transverse, oblique and unstable lie, second twin, polyhydramnios, unengaged presenting part, low-lying placenta
• Procedure related- ARM with high presenting part, vaginal manipulation of the foetus with ruptured membranes, ECV, large balloon catheter induction of labour, stabilising induction of labour
• Approximately 50% of reported cases are preceded by obstetric intervention- in general these procedures cause cord prolapse by presenting close application of the presenting part to the lower part of the uterus/pelvic brim.

There Is some suggestion that cord abnormalities, such as true knots, low content of Wharton’s jelly and a single umbilical artery are associated with a higher chance of prolapse

Question 4

Can USS be used to predict risk

Answer 4

Routine USS is not sufficiently sensitive or specific for identification of cord presentation and should not be performed to predict increased risk (could be considered in breech presentation when planning vaginal delivery.)

Question 5

Presentation/ investigations for cord prolapse

Answer 5

• Cord presentation or prolapse should be excluded at every vaginal examination in labour and after SROM if risk factors are present
• The foetal heart rate should also be auscultated after every vaginal examination in labour and after SROM
• When SROM occurs, if there is normal foetal heart rate monitoring and there are no risk factors for cord prolapse, then a routine vaginal examination is not indicated
• Cord prolapse should be suspected when there is abnormal foetal heart rate pattern, especially if such changes commence soon after membrane rupture, either spontaneous or artificial
• Speculum and/or digital VE should be performed when cord prolapse is suspected

Question 6

How can umbilical cord prolapse be prevented

Answer 6

• With transverse, oblique or unstable lie, elective admission to hospital after 37+0 weeks of gestation should be discussed and women in the community should be advised to present urgently if there are signs of labour or suspected ROM
• Women with non-cephalic presentations and P-PROM should be recommended inpatient care
• ARM should be avoided if the presenting part is high or mobile
• If ARM is necessary in these circumstances, provision should be made for immediate caesarean section
• Upward pressure on the presenting part should be kept to a minimum in women during VE and other obstetric interventions in the context of ruptured membranes because of the risk of upward displacement and cord prolapse
• Rupture of membranes should be avoided if on VE the cord is felt below the presenting part- when cord presentation is diagnosed in established labour, C-section is usually indicated

Question 7

What is it immediate management of umbilical cord prolapse

Answer 7

• When cord prolapse is diagnosed before full dilatation, assistance should be called and preparations made for immediate birth in theatre
• NOT RECOMMENDED to manually replace prolapsed cord
• To prevent vasospasm, there should be minimal handling of loops of cord lying outside the vagina
• To prevent cord compression, it is recommended that the presenting part be elevated manually OR by filling the urinary bladder
• Manual elevation is achieved by inserting two fingers into the vagina and pushing the presenting part upwards (but excessive elevation may encourage more cord to prolapse
• Cord compression can be further reduced by the mother adopting the knee-chest or left later position (preferably with head down and pillow under left hip)
• Tocolysis can be considered while preparing for C-section if there are persistent CTG abnormalities (should NOT result in delay)- terbutaline 0.25mg subcutaneously

Question 8

Mode of delivery preferred in cord prolapse

Answer 8

• C-section is the recommended mode of delivery in cases of cord prolapse when vaginal birth is not imminent in order to prevent **hypoxic acidosis **
• A CATEGORY 1 C-SECTION should be performed with the aim of achieving birth within 30 minutes or less is the prolapse is associated with a suspicious or pathological foetal HR, without compromising maternal safety
• Category 2 section can be considered for women in whom the foetal HR is normal, but continuous assessment of the heart trace is essential- If the CTG becomes abnormal, re-categorisation to category 1 birth should be considered
• Verbal consent is satisfactory for a category 1 section
• Vaginal birth, in most cases operative, can be attempted at full dilatation if it is anticipated that birth would be accomplished quickly and safely
• Paired cord blood samples should be taken for pH and base excess measurement.

Question 9

Management of umbilcial cord prolpase in the community

Answer 9

• Midwives should assess the risk of cord prolapse for women requesting hoe births or in birth centres without theatre access
• Women with known cord prolapse should be advised to assume the knee-chest face-down position while waiting for hospital transfer
• During emergency ambulance transfer, the knee-chest position is potentially unsafe, and the exaggerated Sims position should be used
• All women with cord prolapse should be advised to be transferred to the nearest consultant-led unit for birth, unless an immediate vaginal examination reveals that a spontaneous vaginal birth is imminent
• The presenting part should be elevated during transfer either manually or by using bladder distension. There should be minimal handling of cord lying outside the vagina

Question 10

Risk of perinatal mortality after cord prolapse outside hospital

Answer 10

More than 10x increased risk

Question 11

Management of cord prolapse at the threshold of viability

Answer 11

• Expectant management should be discussed for cord prolapse complicating pregnancies with a gestational age at the threshold of viability (23+0 to 24+6 weeks).
• Should be counselled on both continuation and termination of pregnancy at this threshold
• SHOULD NOT replace the cord into the uterus when prolapse occurs at or before the threshold of viability

Question 12

Foetal blood sampling indications, contraindications and reference ranges

Answer 12