Delayed Cord Clamping (DCC) WoS MCN, Obstetrics

The transition to extra-uterine life is a complex physiological process comprising several different mechanisms that must happen simultaneously.

In optimal circumstances, spontaneous breathing aerates the lung and leads to a fall in pulmonary vascular resistance and subsequent increased pulmonary blood flow¹. This transition requires additional blood volume which is drawn from the low resistance placental circulation². Immediate clamping of the cord interrupts this normal physiological process and can reduce venous return to the heart by 30-50%³, subsequently reducing cardiac output which can lead to circulatory collapse in the preterm infant⁴.  When cord clamping precedes aeration of the lungs this reduction in cardiac output could potentially result in reduced cerebral blood flow which has been shown to be associated with intraventricular haemorrhage (IVH)¹.

Delaying cord clamping has been shown to result in a 20-30% increase in blood volume^5,6. A Cochrane review in 2012 demonstrated that DCC in preterm infants can lead to improved circulatory stability, less need for blood transfusion, reduced incidence of necrotising enterocolitis and a lower risk of IVH⁷. Delayed card clamping is now recommended by the major resuscitation councils^8-10.

BENEFITS of DCC for PRETERM infant include:

• Reduced need for inotropic support (RR 0.42 (95%CI 0.23-0.77)⁷.
• Reduced incidence of NEC (5 trials 241 infants, RR 0.62 95%CI 0.43-0.90) ⁷.
• Less need for blood transfusion (7 trials, 392 infants: RR 0.61 95% CI 0.46 – 0.81) ⁷.

A recent meta-analysis including 18 trials with 2834 infants demonstrated a significant reduction in mortality (RR0.68 95%CI 0.52-0.90, NNT33)¹¹. This analysis was heavily weighted on one study were the adherence to DCC was 73.2%. The majority of these infants received Immediate Cord Clamping (ICC) due to clinical concerns of the infant. It did not demonstrate any reduction in IVH or NEC as shown by previous reviews¹².                                                                       

RISKS of DCC for PRETERM infant include:

• higher peak bilirubin level in infants receiving DCC (7trials 320 infants; ~difference 15mmol/L 95%CI 5.62-24.40) ⁷.

BENEFITS of DCC for TERM baby include:

• higher birth weight (12 trials, 3139 infants mean difference 101.18g 95%CI 45-157) ¹³.
• Higher haemoglobin concentration (mean difference 2.17g/dl 95%CI 4.06-0.28) ¹³.
• Lower incidence of iron deficiency (RR2.65 95%CI 1.04 – 6.73) ¹³.
• Improved fine-motor and social domains at 4 years of age ¹³.

RISKS of DCC for TERM baby include:

• The infants receiving DCC required more phototherapy (97 trials 2324 infants, 2.47% vs 4.36% 0.62 95%CI 0.41 – 0.96) ¹³.

Cord Milking - N.B. Not currently recommended in babies <28 weeks

One of the contraindications to performing DCC is a requirement for immediate resuscitation⁹ and this is the most common cause for DCC not being performed in practice as reported in the literature¹². Cord milking has been proposed as an alternative to DCC whereby placental transfusion can be achieved in 20s¹⁵, therefore reducing delay in resuscitation. Intact umbilical cord milking (UCM) is where the cord is grasped and blood is pushed toward the baby prior to clamping¹⁶. The exact technique varies between studies, a milking speed of 20cm/2s with a frequency of 3-5 times are most frequently described in the literature¹.

A meta-analysis comparing UCM to ICC demonstrated that UCM was associated with less IVH all grades (5 trials 277 infants: RR0.62 95%CI 0.41-0.93), less chronic lung disease (5 trials, 191 infants: 0.42 95%CI 0.21-0.83) and higher haemoglobin (3 trials, 159 infants; ~20g/dL 95%CI 0.21-0.83)¹⁷.

A RCT comprising 197 infants <33 weeks comparing UCM to DCC have demonstrated that UCM is beneficial in infants born by caesarean section. These infants had higher SVC blood flow and higher RVO measures in first 12 hours of life, a higher Hb, better delivery room temperature, higher BP in first 15h and higher urine output in the first 24 hours¹⁸. This is potentially as more blood remains in the placenta at birth due to anaesthetic and surgical interventions interfering with active uterine contractions¹.

N.B. A recent study comparing UCM to DCC ²⁹ has demonstrated a significantly increased incidence of severe IVH in the babies under 27 weeks gestation (22% vs 4%).  No comparison was made between UCM and ICC however.  This raises sufficient concerns regarding UCM in the very preterm and we do not currently recommend this option. 

Practice Point: As there is less evidence to support this strategy, it should only be used when there is an urgent need to commence resuscitation, for mother or infant, which precludes a delay of at least 60 seconds to allow a normal placental transfusion.

Resuscitation with an intact cord.

It is becoming increasingly recognised that timing on onset of lung aeration in relation to cord clamping has important physiological effects. An study in preterm lambs demonstrated ventilation prior to clamping cord resulted in improved cardiovascular function by increasing pulmonary blood flow before the cord is clamped and subsequently stabilising cerebral haemodynamic transition¹⁹. Observational studies in human infants have demonstrated increased admission, mortality²⁰, CLD, and severe IVH²¹ if the cord is clamped prior to onset of breathing.

The COIN study; A pilot RCT comprising 276 infants compared resuscitation with delayed cord clamping of at least 2 minutes versus cord clamping of <20s and resuscitation after clamping. This study demonstrated that resuscitation with an intact cord is feasible; there was less death in the resuscitation with intact cord group, however this did not reach statistical significance and there was no difference in any neonatal or maternal outcomes²².

A smaller RCT with 150 infants compared 60s of DCC with stimulation to 60s of DCC with stimulation and positive pressure ventilation +/- CPAP via mask. This again demonstrated this is a feasible method and showed no significant difference in outcomes²³.

Practice point: This approach will only be possible in units where there are facilities to allow resuscitation to occur at the maternal bedside.

There is strong evidence that demonstrates DCC is beneficial and therefore performing delayed cord clamping for 60 seconds is recommended in all eligible infants.

When immediate resuscitation is needed the best method remains unclear. In this situation cord milking or resuscitation with an intact cord (if appropriate resources and trained staff are available) can be considered on an individual basis. Further research is required before these interventions can be implemented as standard practice.

The Cochrane Collaboration.

“A more liberal approach to delaying clamping of the umbilical cord in healthy term infants appears to be warranted, particularly in light of growing evidence that DCC increases early haemoglobin concentrations and iron stores in infants.  DCC is likely to be beneficial as long as access to treatment for jaundice requiring phototherapy is available”¹³.

National Institute for Clinical Excellence (NICE).

“Do not clamp the cord earlier than 1 minute from the birth of the baby unless there is concern about the integrity of the cord or the baby has a heartbeat below 60 beats/minute that is not getting faster”²⁴.

Royal College of Obstetrics and Gynaecology (RCOG).

“In healthy term babies, the evidence supports deferring clamping of the umbilical cord, as this appears to improve iron stores in infancy. Jaundice may be more common after deferred cord clamping but this management is likely to be beneficial as long as phototherapy for jaundice is available. This assessment of the evidence is concordant with the Cochrane review and the recommendations by NICE”²⁵.

All babies will be eligible for delayed cord clamping unless there is:

• A requirement for immediate resuscitation.
• Cord issues i.e. no pulsation, cord snapping or incision, limited cord length.
• Placental abruption or early separation.
• Uterine inversion.
• Monochorionic twins (where risk of placental vessel anastomoses may result in draining of blood from twin 2 to twin 1 during DCC procedure).
• Maternal concern e.g. PPH, shock, seizure etc.

It is the position of this guidance to state that Delayed Cord Clamping (DCC) is the normal, physiological process that supports transition to extra-uterine life with Early Cord Clamping (ECC) seen as a non-physiological clinical intervention, supported by the best practice recommendations above.

As with all aspects of the care we deliver the provision of clear parental information, with opportunity for discussion and questions, is essential.  This should take place during the antenatal period, or early intrapartum period, and should refer to the best practice recommendations above.  Within the lower risk group (>35 weeks gestation), clear discussion of the risks, especially jaundice and its subsequent treatment and care, should be undertaken.  On consideration of the information provided parents may opt for the intervention of early cord clamping.  This decision should be fully acknowledged and supported by clinical staff.

It is recommended that staff training; resources to identify and diagnose jaundice; equipment to provide and manage phototherapy and inpatient/outpatient service provision should be available where DCC is undertaken.

Administration of prophylactic uterotonic drugs i.e. syntocinon, should not be delayed as they have no proven impact on the efficacy of DCC²⁵.  However, there is variation in the timing of the administration of uterotonic drugs and their use dependent on context and location i.e. physiological third stage, active management of the third stage and local unit policy.

There is no observed increased risk of PPH, or the need for manual removal of placenta, following DCC¹³.

Gravity and position of the baby during DCC does not appear to have a significant effect on the volume of placental transfusion achieved following birth at term²⁶.  This would allow appropriate positioning of the baby to achieve skin-to-skin and may improve overall acceptance and achievement of DCC by parents and staff.  No studies involving preterm infants have replicated these findings therefore a sensible position should be observed (see procedure guidance below).

Both arterial and venous cord blood gas results may be altered, dependent on timing of cord clamping, making interpretation of results more challenging²⁷.  Although the impact on these results is likely to be small, clear and accurate recording of when samples are obtained will be essential to support robust analysis and interpretation²⁵.

Appropriate gestational thermal care of the neonate should be managed as per WOS MCN Guidance to ensure cold injury does not result from delayed cord clamping procedure.

In the PRETERM INFANT: <35 weeks gestation for purposes of this guidance.

• Following delivery the baby should be wrapped, or placed in a plastic bag, dependent on gestational age.
• Positioning of the baby will depend on mode of delivery and condition at birth:

1. Vaginal Birth: The baby should be held below the level of the perineum, and definitely no more than 20cms above the introitus¹³.
2. Caesarean Section Delivery: The baby should be held below the level of the incision site, and definitely no more than 10cms above the uterus¹³.

• The condition of the infant should be assessed and the cord observed for pulsation during the procedure
• There should be a delay of at least 1 minute before clamping of the cord, unless the cord pulsation ceases or the infant requires immediate resuscitation, or if there are maternal concerns. (NB Where facilities are available resuscitation may be commenced whilst undergoing DCC)

In the TERM INFANT: 35+0 Gestation or above for purposes of this guidance.

1. Following a Vaginal Birth:

• The baby is delivered and routine drying and stimulation takes place.
• The baby can go into skin-to-skin contact within the constraints of the length of umbilical cord.
• Clamping and cutting of the umbilical cord is delayed to allow placental transfusion²⁸, unless mother or baby requires resuscitation, according to the agreed management plan for the 3^rd stage of labour (i.e. physiological or active management). With physiological management there is no routine use of uterotonic drugs, no clamping of the cord until pulsation has stopped and the placenta is delivered by maternal effort.  With active management a uterotonic drug is given and the cord is clamped by 5 minutes in order that controlled cord traction can be undertaken following signs of placental separation²⁴.

2. Following a Caesarean Section Delivery:

• The baby should be held below the level of the incision site, and definitely no more than 10cms above the uterus.
• Consideration must be given to prevention of heat loss during the procedure i.e. warm, sterile towel placed over the baby throughout.
• There should be a delay of at least 1 minute before clamping of the cord, unless the cord pulsation ceases or the infant requires immediate resuscitation, or if there are maternal concerns.

The following flow chart has been developed for quick reference

Practice Point: Administration of Uterotonic drugs should not be delayed during DCC

Early cord clamping versus delayed cord clamping or cord milking for preterm babies⁷.

In the womb, the baby’s blood flows through the umbilical cord to and from the baby and the placenta bringing oxygen and nutrition to the baby from the mother’s blood. If the umbilical cord is left unclamped for a short time after the birth, some of the blood from the placenta passes to the baby (this is called placental transfusion) to increase the baby’s blood volume and help the flow of blood to the baby’s important organs including the lungs. For many years now, standard care during the delivery of the placenta has been to clamp the cord immediately at birth. This review looks at delaying cord clamping to allow more placental transfusion compared with immediate cord clamping. The other intervention considered is “milking the cord” which means the caregiver holds the cord and squeezes blood down the cord into the baby. In this review we have included 15 randomised controlled trials with 738 babies born prematurely between 24 and 36 weeks’ gestation by caesarean section or vaginal birth. These studies compared babies where the cord was clamped within a few seconds of the birth with those whose cords were clamped after a delay of at least 30 seconds. The maximum delay in cord clamping was 180 seconds. Providing babies with additional blood through delayed cord clamping or milking the cord before clamping appeared to help the babies to adjust to their new surroundings. Fewer babies needed transfusions for anaemia, the risk of bleeding in the brain (intraventricular haemorrhage) and the risk of necrotising enterocolitis (a severe infection in the bowel) were reduced. The trials had an unclear risk of bias and varied outcome definitions were used. Further studies are needed comparing methods of delivering placental blood to babies to see which has the most benefit.

Effect of timing of umbilical cord clamping of term infants on mother and baby outcomes¹³.

At the time of birth, the infant is still attached to the mother via the umbilical cord, which is part of the placenta. The infant is usually separated from the placenta by clamping the cord. This clamping is one part of the third stage of labour (the time from birth of the baby until delivery of the placenta) and the timing can vary according to clinical policy and practice. Although early cord clamping has been thought to reduce the risk of bleeding after birth (postpartum haemorrhage), this review of 15 randomised trials involving a total of 3911 women and infant pairs showed no significant difference in postpartum haemorrhage rates when early and late cord clamping (generally between one and three minutes) were compared. There were, however, some potentially important advantages of delayed cord clamping in healthy term infants, such as higher birthweight, early haemoglobin concentration, and increased iron reserves up to six months after birth. These need to be balanced against a small additional risk of jaundice in newborns that requires phototherapy.