This study aimed to compare the effects of oxytocin and carbetocin, commonly used uterotonics in postpartum hemorrhage prophylaxis, on maternal electrolyte balance. In this retrospective cohort study, a total of 750 women who underwent elective cesarean delivery and received prophylactic uterotonics with either oxytocin (n = 375) or carbetocin (n = 375) were included. Demographic, obstetric, and perioperative characteristics were recorded. Serum electrolyte levels were measured preoperatively and at the 6th and 24th postoperative hours. The primary outcome was the change in serum sodium (ΔNa), while the secondary outcomes included the incidence of hyponatremia, urine output, other electrolyte levels, and blood loss. Multivariable linear regression analysis was performed to identify independent predictors of sodium change. The groups were comparable in terms of demographic and obstetric characteristics. The decrease in serum sodium levels at the 6th and 24th postoperative hours was more pronounced in the oxytocin group, whereas the values remained more stable in the carbetocin group (p < 0.01). The 24-h ΔNa was higher in the oxytocin group, showing a wider distribution and a tendency toward negative values, while the median ΔNa in the carbetocin group was closer to zero. Regression analysis demonstrated that carbetocin use, compared with oxytocin, was independently associated with a more favorable sodium profile (β = 0.916, 95% CI 0.43–1.41, p < 0.001). Additionally, preoperative sodium level was identified as a significant predictor of ΔNa (β = − 0.125, p = 0.046). Other variables (age, BMI, gestational week, blood loss, transfusion) had no significant effect. Although both oxytocin and carbetocin are effective in postpartum hemorrhage prophylaxis, they exert different effects on electrolyte balance. Oxytocin led to a more pronounced decrease in sodium levels, whereas carbetocin provided a more stable profile. These results suggest that carbetocin may represent a safer alternative in terms of electrolyte balance, particularly in patients where fluid management is critical.
Özler et al. (Mon,) studied this question.