Interrelations Between Four Antepartum Obstetric Interventions and Cesarean Delivery in Women at Low Risk: A Systematic Review and Modeling of the Cascade of Interventions

ObjectivesTo critically appraise the literature on the relations between four intrapartum obstetric interventionselectronic fetal monitoring (EFM), epidural analgesia, labor induction, and labor acceleration; and two types of deliveryinstrumental (forceps and vacuum) and cesarean section. MethodsThis review included meta-analyses published between January 2000 and April 2012 including at least one randomized clinical trial published after 1995 and presenting results on low-risk pregnancies between 37 and 42weeks of gestation, searched in the databases Medline, Cochrane Library, and EMBASE with no language restriction. ResultsOf 306 documents identified, 8 fulfilled the inclusion criteria and presented results on women at low risk. EFM at admission (vs intermittent auscultation) was associated with cesarean delivery (odds ratio [OR]=1.20, 95% confidence interval [CI] 1.00-1.44) and epidural analgesia (OR=1.25, 95% CI 1.09-1.43). Epidural on request was associated with cesarean delivery (OR=1.60, 95% CI 1.18-2.18), instrumental delivery (OR=1.21, 95% CI 1.03-1.44), and oxytocin use (OR=1.20, 95% CI 1.01-1.43) when compared with epidural on request plus nonpharmacological labor pain control methods such as one-to-one support, breathing techniques, and relaxation. Induction and acceleration of labor showed heterogeneous patterns of associations with cesarean delivery and instrumental delivery. ConclusionsComplex patterns of associations between obstetric interventions and modes of delivery were illustrated in an empirical model. Intermittent auscultation and nonpharmacological labor pain control interventions, such as one-to-one support during labor, have the potential for substantially reducing cesarean deliveries.