Best for baby
To work out best practice, we need to start by investigating current practice.
When an umbilical cord is left unclamped after birth, a significant proportion of the blood from the placenta flows into the newborn, contributing to approximately one-quarter of total potential blood volume. The routine intervention of immediate cord clamping was introduced over half a century ago, to assist the birth of the placental and to help reduce maternal blood loss. It has become a growing cause for concern due to the potential harm of preventing the newborn access to its placental blood and subsequent reduction in iron levels.
For her Masters of Midwifery Tina Hewitt investigated cord clamping practice in a New Zealand tertiary hospital. A stopwatch was used to time the cord clamping interval at 55 full term vaginal births. Cord clamping times were analysed against the mode of birth (spontaneous or instrumental), the maternal position for birth and the healthcare practitioners involved in the birth. Cord clamping timing ranged from a minimum of 14 seconds to a maximum of 34 minutes. The median umbilical cord clamping time for all births in the study was 3.5 minutes, which aligned with current local, national and international guidelines.
Tina found that midwives are likely to facilitate longer cord clamping times as they are more likely than doctors to attend spontaneous uncomplicated births which do not warrant immediate separation of mother and baby for preventative or resuscitative measures. Two key drivers as to when the cord is clamped are the management of placental birth and the need for newborn resuscitation. Further research is needed to help identify the optimal time for cord clamping, whether that is a measured time limit or linked to factors such as neonatal breathing efforts. Knowledge of the ways in which birth factors influence cord clamping times may also assist birth practitioners in identifying areas to improve practice.
Tina Hewitt's thesis was supervised by Sally Baddock and Jean Patterson.
Image credit: Lou Bueno, used under Creative Commons licence CC BY-NC-ND 2.0