- © 2007 Canadian Medical Association or its licensors
Shiliang Liu and colleagues conclude that the risks of severe maternal morbidity associated with planned cesarean delivery are higher than those associated with planned vaginal delivery.1 However, a cross-sectional study of associations is nondirectional and one cannot infer either the presence of causality or its direction.
During the 14-year study period, the rate of cesarean deliveries was increasing and morbidity was probably decreasing. Associations between 2 heterogeneous data sets are not meaningful. One needs data from a recent homogeneous time period to produce statistical associations that are relevant for current practice.
Finally, the authors acknowledge that although the morbidity rate differences were statistically significant, the absolute differences were small. The authors do not state which, if any, of these small differences were clinically significant.
Footnotes
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Competing interests: None declared.
REFERENCE
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