Figure 1 is a flow diagram of the population of women included in this study. Between January 2017 and April 2020, 26,465 women delivered in the Guatemalan clusters of the MNHR. 3,143 women, 11.9% of the MNHR population had a history of prior cesarean delivery and a singleton gestation. 2,210 (79.9%) women with a history of prior cesarean birth had data available on mode of delivery and gave birth by repeat cesarean; 1312 (59.4%) were pre-labor cesareans while 896 (40.5%) were intrapartum cesarean births.
Table 1 presents the sociodemographic and obstetric/labor characteristics of the population overall and by timing of cesarean. The population was median age 27 with interquartile range (IQR) 23 to 31 years. Most women had schooling (95.8%), more than half were primiparous (58.6%), and 28.6% were of normal body mass index (BMI). Women who delivered by intrapartum cesarean birth (as compared to pre-labor cesarean) were statistically more likely to be younger (median age 26 versus 27), less likely to have had schooling (94.0% versus 96.0%), and more likely to be underweight or normal weight (32.6% versus 26.7%), p 0.05. The median interpregnancy interval of women experiencing intrapartum cesarean was shorter (26.3 versus 30.3) and they experienced less hypertensive disease (4.8% versus 8.4%), p < 0.05. For these same women, those undergoing intrapartum cesarean birth, they experienced more obstructed labor (7.2% versus 2.7%) and were more likely to deliver in the hospital (95.8% versus 91.1%) compared to “other” locations, p < 0.05.
Table 2 shows maternal and neonatal outcomes that varied in bivariate comparisons by timing of cesarean birth. Magnesium sulfate was administered to more women undergoing pre-labor cesarean (7.3% versus 4.2%), and the rate of postpartum infection was higher with pre-labor cesarean birth than intrapartum (0.5% versus 0.0%), p < 0.05. With respect to neonatal outcomes, none were statistically different between the two types of cesarean.
Table 3A shows multivariable modeling of timing of cesarean including all variables occurring prior to delivery significant in bivariate comparisons (delivery location, hypertensive disorders of pregnancy, labor dysfunction, interpregnancy interval, BMI, education, and age). The table shows variables that were associated with intrapartum cesarean birth when compared to pre-labor cesarean birth. Those associated with an increased risk of intrapartum cesarean birth included hospital delivery as compared to “other” location (ARR 1.6 [1.2,2.1]) and dysfunctional labor (ARR 1.6 [1.4,1.9]). Variables associated with a reduced risk of intrapartum cesarean birth were hypertensive disease (ARR 0.7 [0.6,0.9]), schooling (ARR 0.9 [0.8,0.9]), and increasing age, which was associated with a very slight reduction in the outcome (ARR 0.99 [0.98,0.99]).
Table 3B shows the significant results of individual regressions were timing of cesarean was tested as the dependent variable with the maternal outcomes that differed in bivariate comparisons as the indepent variable. These outcomes included postpartum infection and magnesium. Each regression was adjusted for delivery location, hypertensive disease, dysfunctional labor, education, and age. Postpartum infection did not occur after intrapartum cesarean birth, so the model did not converge, and the adjusted relative risk of needing magnesium did not vary by timing of cesarean birth. No neonatal outcomes were tested as none were significant in bivariate comparisons.