Objectives: The RTI International-University of North Carolina at Chapel Hill Evidence-based Practice Center (RTI-UNC EPC) systematically reviewed the evidence on the trend and incidence of cesarean delivery (CD) in the United States and in other developed countries, maternal and infant outcomes of cesarean delivery on maternal request (CDMR) compared with planned vaginal delivery (PVD), factors affecting the magnitude of the benefits and harms of CDMR, and future research directions.
Data sources: We searched MEDLINE, Cochrane Collaboration resources, and Embase and identified 1,406 articles to examine against a priori inclusion criteria. We included studies published from 1990 to the present, written in English. Studies had to include comparison between the key reference group (CDMR or proxies) and PVD.
Review methods: A primary reviewer abstracted detailed data on key variables from included articles; a second senior reviewer confirmed accuracy.
Results: We identified 13 articles for trends and incidence of CD, 54 for maternal and infant outcomes, and 5 on modifiers of CDMR. The incidence of CDMR appears to be increasing. However, accurately assessing either its true incidence or trends over time is difficult because currently CDMR is neither a well-recognized clinical entity nor an accurately reported indication for diagnostic coding or reimbursement. Virtually no studies exist on CDMR, so the knowledge base rests chiefly on indirect evidence from proxies possessing unique and significant limitations. Furthermore, most studies compared outcomes by actual routes of delivery, resulting in great uncertainty as to their relevance to planned routes of delivery. Primary CDMR and planned vaginal delivery likely do differ with respect to individual outcomes for either mothers or infants. However, our comprehensive assessment, across many different outcomes, suggests that no major differences exist between primary CDMR and planned vaginal delivery, but the evidence is too weak to conclude definitively that differences are completely absent. Given the limited data available, we cannot draw definitive conclusions about factors that might influence outcomes of planned CDMR versus PVD.
Conclusions: The evidence is significantly limited by its minimal relevance to primary CDMR. Future research requires developing consensus about terminology for both delivery routes and outcomes; creating a minimum data set of information about CDMR; improving study design and statistical analyses; attending to major outcomes and their special measurement issues; assessing both short- and long-term outcomes with better measurement strategies; dealing better with confounders; and considering the value or utility of different outcomes.