Diaz-Castro et al. (2014) discovered that neonates who had experienced DCC were likely to demonstrate higher superoxide dismulase activity. They surmise that this may help protect neonates against the oxidative stress that is caused by labour. Bhatt et al.’s (2013) work has demonstrated that there is a smoother transition to life for premature lambs who have delayed cord clamping and Langli Ersdal et al.’s (2014) work supports this hypothesis in human neonates. They surmise that this is because the pulmonary blood flow is improved with improved cardiac function. Langli Erdal et al. (2014) report, after their large observational study, that if the cord is clamped after spontaneous respiration, then the baby is at less risk of dying during transition to life. Hooper et al. (2015) explain that this may be because establishing respiration before clamping the cord reduces pulmonary resistance and increases preload to increase cardiac output.

Bhatt et al. (2013) conclude that blood flow is reduced to the left atrium when the cord is clamped, which effectively reduces cardiac output at a critical time in transition. The increased blood flow in the superior vena cava when DCC occurs may decrease rates of intra-ventricular haemorrhage, which is associated with decreased cerebral blood flow (Meyer & Mildenhall, 2012). Later research has confirmed the thought that the stabilising of cerebral blood flow may decrease the risk of cerebral injury during transition to extra-uterine life (Bhatt et al., 2013; Nevill & Meyer, 2015). Mercer et al. (2008) suggest that it could be an inflammatory response to hypovolaemia which was causative for some cases of cerebral palsy. Diaz-Castro et al. (2014) mention moderation of inflammatory effects with DCC, but do not link it to a particular pathology.

Mercer et al. (2008) suggest babies who have DCC will have 30 percent more blood volume. Farrar et al.’s (2011) research suggests that DCC allows a placental transfusion, which comprises between one quarter to one third of the neonate’s blood volume. Mercer et al. (2010) suggest that the lungs receive about eight percent of cardiac output before birth, increasing to 45 percent after birth. The extra blood volume may be needed to service organs that have not been fully functioning in-utero (Mercer et al., 2010).

The increase in blood volume available to the baby after DCC, gives the expectation that neonates receiving this care would be less likely to need a blood transfusion, as was confirmed by Rabe et al. (2012). However, Elimian et al. (2014) demonstrated that there was no difference in the need for blood transfusions between 200 randomised preterm infants who experienced DCC and those who did not. As Elimian et al. (2014) acknowledges, the delay in their study was only 30 seconds, which may be inadequate to allow for sufficient blood transfer, whereas Rabe et al.’s (2012) studies DCC for 30 to 120 seconds. To allow for longer DCC without the concern of needing to remove the baby for resuscitation, this work could be repeated using bedside resuscitation trolleys (Hutchon, 2012). This would enable resuscitation, where needed, with an intact cord.

Smit et al. (2014) have identified an increase in oxygen saturation in the first few minutes of life where DCC occurred. Although heart rates were observed to be lower in this period with DCC, it was theorised that with increased blood volume the heart would not have to work as hard to circulate blood effectively (Smit et al., 2014). In other research Tiemermsa et al. (2015) found increased weight gain at two months of age for low birth weight babies who had DCC. McDonald et al. (2013) only mentions increased weights at birth with DCC, which may be expected with increased blood passing the baby, but no mention is made as to how long this increase in weight lasted.