Classification of primary caesarean sections in labor and its usefulness for analysis of Slovenian perinatal data

OBJECTIVE: To determine the usefulness of a novel classification of indications for caesarean section (CS) in labour in recognizing differences in clinical practice in different maternity units. METHODS: Data from the National Perinatal Information System (NPIS) for 2013 and 2014 were used to classify indications for CS in nulliparous women with spontaneous onset of labour at ≥37 weeks with single cephalic foetuses within 14 Slovenian maternity units into foetal distress and different sub-groups of dystocia according to use and dosage of oxytocin. Chi-square test was used for statistical comparison between units (P≤0.05 significant). RESULTS: There were 13,572 deliveries and 1,567 (12.0%) CS in nulliparous patients with spontaneous onset of labour at ≥37 weeks with single cephalic foetuses in Slovenia during the study period. Rates of CS in this group of women differed significantly among different maternity units (from 4.1% to 20.9%; P<0.001) suggesting significant differences in clinical practice. The most common indication for CS was cephalopelvic disproportion, which was diagnosed with different frequency in different units (from 11.2% to 45.9%; odds ratio 6.72; 95% confidence interval 3.10- 14.71; P<0.001). CONCLUSIONS: It is possible to use NPIS data to retrospectively classify indications for CS. Such classification reveals significant differences among maternity units and could allow for a meaningful analysis of CS rates in different hospitals leading to evidence-based initiatives to decrease the incidence of primary CS.