Detection of Nuchal Cord Based on Specific CTG Patterns Intrapartum - A Myth?

Nuchal cord, the situation when the umbilical cord is wrapped around the neck of the fetus, is a common occurrence during pregnancy and intrapartum. Abnormal cardiotocography patterns (CTG patterns) during nuchal cord are usually not associated with increased perinatal morbidity. This retrospective data analysis aimed to investigate the occurrence of specific CTG patterns with nuchal cord.

150 CTGs with and 150 CTGs without nuchal cord at 60 and 30 minutes prior to delivery were randomly selected from the obstetric database of Hanover Medical School out of a total cohort of 7573 births (spontaneous delivery, vaginal-operative delivery, secondary caesarean section) between 2014 and 2017. After anonymization in accordance with the 2015 FIGO criteria, CTG patterns were interpreted by three physicians with varying levels of professional experience. The physicians were also asked to assess whether nuchal cord was present or not. The interrater variability between investigators regarding the interpretation of the CTG patterns was also investigated using proportion of agreement and kappa statistics.

Nuchal cord was present in 11% of the total cohort. The study cohort and the total cohort were equivalent in terms of patient characteristics. No significant differences were found in the assessments of the three physicians with regard to CTGs with and without nuchal cord. Likewise, logistic regression analysis was unable to identify a specific CTG pattern in cases with nuchal cord intrapartum. High interpretation variability between physicians was found regarding CTG interpretations (PoA > 0.5).

CTG interpretation just before delivery of the infant is not useful to detect nuchal cord. Moreover, despite the existence of defined criteria, the variability between the CTG interpretations of the three physicians was high.