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

We aimed to compare maternal morbidity and mortality of cesarean sections (CS) in the second versus first stage of labor.

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.

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.

Second-stage CS is associated with higher rates of adverse maternal outcomes, mainly unintentional uterine incision extension, uterine atony, and suspected endometritis.