Timing of cord clamping: An observational study of cord clamping practice in a maternity hospital in Aotearoa New Zealand

Abstract

Background: When the umbilical cord is left unclamped after birth, a significant proportion of the blood from the placenta flows into the newborn, increasing the baby's blood volume by approximately 30%. Routine intervention of immediate cord clamping is harmful as it deprives the newborn access to their own blood, resulting in impaired physiological transition at birth and lower iron stores in early infancy. Iron deficiency in early life, even without anaemia, is linked with impaired neurodevelopment. Aim: The aim of this study was to accurately record birth to cord clamping interval at term vaginal births in a tertiary hospital in Aotearoa New Zealand and concurrently to examine some of the circumstances that may influence the timing of when the cord is cut. Method: This observational study was undertaken from August 2017 to April 2018. Participants were pregnant women having a vaginal birth at ≥37 weeks gestation. Data collected included birth to cord clamping interval, mode of birth (spontaneous or instrumental), maternal position for birth and practitioners involved in the birth. Descriptive statistics were used to summarise the data. Results: Participants were 55 women with term vaginal births. The median interval between birth and cord clamping was 3.5 minutes (IQR 2.18 - 5.68 mins). There was a longer median cord clamping time in the group who had a spontaneous birth (median 3.71; IQR 2.67 - 6.23) vs instrumental birth (2.08; IQR 0.55 - 2.30); with maternal side-lying position (6.37; IQR 4.15 - 9.48) vs lithotomy position (2.24; IQR 1.87 - 3.50); with midwife-facilitated birth (4.06; IQR 2.68 - 6.65) vs obstetric-facilitated birth (2.13; IQR 1.48 - 3.28); and when the neonatal team was not called to attend (4.73; IQR3.32 - 8.26) vs when they were called to attend (2.13; IQR 1.28 - 3.27). Discussion: The median cord clamping time of 3.5 minutes aligns with current local, national and international guidelines, although clamping times as short as 0.23 minutes were observed. The study provides a snapshot of practice at one tertiary hospital, examining data on a range of vaginal births, from uncomplicated midwifery-led births to complicated obstetric-led births requiring neonatal team attendance. By identifying some of the circumstances where cords are clamped early, we may be able to modify the associated factors for these births, thereby improving newborn health outcomes in the future.