Differences in outcomes between cesarean section in the second versus the first stages of labor

Objective: We aimed to compare maternal morbidity and mortality of cesarean sections (CS) in the second versus first stage of labor. Study design: Retrospective study of all CS at a single, university-affiliated medical center, between January 2010 and December 2014. Eligibility was limited to term, singleton pregnancies with cephalic presentation. Maternal outcomes of second-stage CS were compared to those of first-stage CS. The primary outcome was defined as estimated blood loss >1000 ml. Results: Overall, 1004 women met the inclusion criteria, of which 290 (29%) had a second-stage CS and 714 (71%) had a first-stage CS. Women in the second-stage CS group had a higher nulliparity and hypertensive disorders rates and a lower rate of previous CS. Second-stage CS was associated with more than double the rate of estimated blood loss >1000 ml (9.7% versus 3.8%, p<.001), and more prone to unintentional uterine incision extension, uterine atony, hemoglobin decrease >2 g/l and antibiotic treatment for suspected endometritis. In a multivariable logistic regression model, second-stage CS was found to be independently associated with unintentional uterine incision extension (OR 6.8, 95% CI 4.1–11.2), uterine atony (OR 3.3, 95% CI 1.4–8.0) and antibiotic treatment for suspected endometritis (OR 2.6, 95% CI 1.4–5.1), but not with excessive blood loss (OR 1.5, 95% CI 0.8–2.8). Additionally, failed assisted vaginal delivery prior to second-stage CS was not associated with a higher rate of complications. Conclusion: Second-stage CS is associated with higher rates of adverse maternal outcomes, mainly unintentional uterine incision extension, uterine atony, and suspected endometritis.