Abstract
Objective: To validate an intrapartum Cesarean Section
Classification System (ICSCS).
Design: Nationwide prospective observational study.
Setting: Twenty-five Norwegian maternity units
Population or Sample: Singleton cephalic pregnancies with
spontaneous or induced labour at ≥ 37 weeks gestation delivering
February-August 2017.
Methods: . After training of all collaborators, Cesarean section
(CS) after spontaneous or induced labour were classified based on fetal
status, dynamic progress in labour, use of oxytocin, frequency of
contractions and linked to denominator data collected and centralized by
the Norwegian Medical Birth Registry.
Main Outcome Measures: Cohens kappa as measure of agreement for
correct application of the classification. Prevalence of the different
groups using the ICSCS within the Ten Group Classification System
(Robson groups).
Results: Of 49 trained experts, 40 (82%) had a κ
>0.6 indicating good or very good level of agreement when
the classification was applied. A total of 1425 CS were classified: CS
classified as fetal indication (no oxytocin) was more common in induced
(Group 2a, 4a, 5b) compared to spontaneous labours (Group 1, 3, 5a). CS
classified as dystocia related to inefficient uterine action and poor
response to oxytocin occurred more often in induced as compared to
spontaneous labours. The prevalence of CS classified as dystocia with
efficient uterine action (malposition or cephalopelvic disproportion)
was low in all Robson groups.
Conclusions: The ICSCS was successfully validated in a national
study. It may become a valuable objective tool for analyzing the
management of labour and explaining differences in the prevalence of CS
between different groups of women.
Funding: Norwegian Medical Association.
Keywords: Cesarean section, classification, induction of labour,
dystocia, fetal distress, Ten-Group-Classification System