Part 2- Prospective data collection
The second part of the study was the prospective data collection. The classification can be used for all women either in spontaneous or induced labour. However the inclusion criteria for the Nor-Why-Cesarean study were singleton pregnancies with a gestational age of more than 36+6 weeks. Exclusion criteria were multiple pregnancies, deliveries at a gestational age < 37 weeks and all pre-labour CSs. For the purpose of the current study, we also excluded all breech deliveries (Group 6 and 7), thus focusing on women in the TGCS groups 1, 2a, 3, 4a and 5a, b, respectively (Fig. 2).
After delivery, the study form of ICSCS, designed in cooperation with the Medical Birth Registry (Supplement 2) was completed by the certified local project collaborators. Guidance for classification, case examples and information about the project was available through access to a cloud-saved project folder. Email contact with the author of the classification (MR) was available for assistance in the confirmation of classification of any cases where there was disagreement. The study forms were sent to the Medical Birth Registry, scanned and read electronically, and data converted into a statistical file format. Data collected in the study was then linked case by case through the unique personal identification number with data routinely collected to the registry from the electronic obstetric patient record.
The proportion of different subcategories in the ICSCS is presented as mean and 95% confidence interval of the mean. Non-overlapping confidence intervals indicate a significant difference between different proportions.
The project took place under the umbrella of the Medical Birth Registry of Norway. Collection of perinatal data to the registry is mandatory without the necessity of written informed consent from the pregnant women. The study was approved by the research ethics committee (REK Nord 2018/1682-3).