Objective: To quantify maternal risk associated with multiple cesarean sections (CSs) and determine whether the third CS defines a threshold for increased morbidity.
Methods: From January 1997 to January 2002, the clinical records of 3191 women who were delivered by CS at our referral maternity center were examined for selected indicators of maternal morbidity. The women were assigned to groups based on number of CSs and the frequency of each indicator was determined. A composite score for each indicator among women grouped by number of consecutive CSs was then derived to compare risk between groups and against the third CS.
Results: By all indicators studied, morbidity increased with successive CSs before and through the third CS. However, compared with the third, the risk of major morbidity was significantly increased with the fifth, and much worse at the sixth CS for placenta previa (odds ratio [OR]=3.8, 95% confidence interval [CI]=1.9-7.4), placenta accreta (OR=6.1, 95% CI=2.0-18.4) and hysterectomy (OR=5.9, 95% CI=1.5-24.4). But the third and fourth CSs had the same risk of major morbidity for placenta previa (OR=1.4, 95% CI=0.8-2.2), placenta accreta (OR=1.0, 95% CI=0.3-2.9) and hysterectomy (OR=0.3, 95% CI=0.0-2.7).
Conclusions: The third CS does not define a threshold for increased risk to the mother. Instead, overall morbidity rises continually with each successive CS. However, specifically for major morbidity from the triad of placenta previa, placenta accreta and hysterectomy during CS, the fourth CS carries the same risk as the third.