Carbetocin and oxytocin use in emergency cesarean delivery: a prospective observational study of 24-hour bleeding outcomes.
In this study, no significant differences were found in bleeding outcomes between carbetocin and oxytocin in women undergoing emergency cesarean delivery. Both medications showed similar rates of additional uterotonic use.
Where it sits
this study against the rest of the carbetocin corpusSummary and findings
This study evaluated 24-hour bleeding-related outcomes in antenatally low-risk women undergoing emergency cesarean delivery who received either carbetocin (100 µg IV) or oxytocin (10 IU IV). The primary outcome was the need for additional uterotonics within 24 hours. No statistically significant differences were observed between the two groups in terms of bleeding outcomes.
Abstract
<h4>Background</h4>Postpartum hemorrhage remains a major cause of maternal morbidity, and cesarean delivery is associated with greater blood loss than vaginal birth. This study evaluated 24-hour bleeding-related outcomes among antenatally low-risk women who received prophylactic oxytocin or carbetocin after National Institute for Health and Care Excellence (NICE) Category 1-2 emergency cesarean delivery and identified intrapartum factors associated with additional uterotonic use.<h4>Methods</h4>This prospective observational, non-randomized comparative study was conducted between October 2024 and August 2025. Antenatally low-risk women admitted for intended vaginal birth who subsequently required NICE Category 1-2 emergency cesarean delivery received oxytocin 10 IU intravenous (IV) or carbetocin 100 µg IV immediately after delivery. The primary outcome was any additional uterotonic use within 24 h. Secondary outcomes were tranexamic acid use, hemoglobin decrease ≥ 2 g/dL at 24 h, absolute hemoglobin change (ΔHb), and postoperative hemoglobin < 8 g/dL. Multivariable logistic regression was performed for the primary outcome.<h4>Results</h4>A total of 300 women were included, with 150 in each group. Additional uterotonic use occurred in 24.0% (36/150) of the carbetocin group and 33.3% (50/150) of the oxytocin group (p = 0.074). Tranexamic acid use did not differ significantly between groups (18.7% vs. 16.0%, p = 0.542). Hemoglobin decrease ≥ 2 g/dL occurred in 68.0% and 60.0%, respectively (p = 0.149). Mean ΔHb was 2.49 ± 1.13 g/dL in the carbetocin group and 2.38 ± 1.03 g/dL in the oxytocin group (p = 0.388). Postoperative hemoglobin < 8 g/dL occurred in 11.3% and 12.0%, respectively (p = 0.981). In multivariable analysis, induction/augmentation (adjusted OR 1.92, 95% CI 1.07-3.42, p = 0.028) and longer duration of membrane rupture (adjusted OR 1.23 per doubling, 95% CI 1.06-1.43, p = 0.006) were independently associated with additional uterotonic use, whereas uterotonic group was not (adjusted OR for oxytocin vs. carbetocin 1.51, 95% CI 0.90-2.54, p = 0.122).<h4>Conclusions</h4>In this prospective observational non-randomized cohort of antenatally low-risk women undergoing emergency cesarean delivery, no statistically significant between-group differences were observed in additional uterotonic use or predefined 24-hour bleeding-related outcomes. Additional uterotonic use was numerically lower with carbetocin, but the difference was not statistically significant. Induction/augmentation and longer duration of membrane rupture were independently associated with higher odds of additional uterotonic use.<h4>Trial registration</h4>ClinicalTrials.gov (NCT07380529), first submitted on 18 January 2026. Retrospectively registered.
Background
Postpartum hemorrhage is a significant cause of maternal morbidity, particularly following cesarean deliveries, which are associated with greater blood loss than vaginal births. Previous studies have suggested that uterotonics like oxytocin and carbetocin may influence bleeding outcomes, but comparative data in emergency cesarean settings are limited. This study aims to fill that gap by evaluating bleeding-related outcomes in women receiving these medications.
Methods
This prospective observational study included 300 antenatally low-risk women who required emergency cesarean delivery. Participants were administered either carbetocin (100 µg IV) or oxytocin (10 IU IV) immediately after delivery. The primary outcome was the need for additional uterotonics within 24 hours, with secondary outcomes including tranexamic acid use, hemoglobin decrease ≥2 g/dL, absolute hemoglobin change, and postoperative hemoglobin levels.
Results
The primary endpoint showed that additional uterotonic use occurred in 24.0% (36/150) of the carbetocin group compared to 33.3% (50/150) in the oxytocin group, with a p-value of 0.074. No significant differences were found in tranexamic acid use (p=0.542), hemoglobin decrease ≥2 g/dL (p=0.149), mean ΔHb (p=0.388), or postoperative hemoglobin <8 g/dL (p=0.981).
Interpretation
The findings indicate no statistically significant differences in bleeding outcomes between carbetocin and oxytocin, aligning with some prior studies that suggest similar efficacy. While the numerically lower additional uterotonic use in the carbetocin group may suggest a potential benefit, the lack of statistical significance and the small effect size limit clinical relevance. The study's observational design and non-randomized nature introduce potential confounding factors.
Key findings
- Additional uterotonic use occurred in 24.0% (36/150) of the carbetocin group and 33.3% (50/150) of the oxytocin group (p=0.074).
- Tranexamic acid use was 18.7% in the carbetocin group and 16.0% in the oxytocin group (p=0.542).
- Hemoglobin decrease ≥2 g/dL occurred in 68.0% of the carbetocin group and 60.0% of the oxytocin group (p=0.149).
- Mean ΔHb was 2.49 ± 1.13 g/dL in the carbetocin group and 2.38 ± 1.03 g/dL in the oxytocin group (p=0.388).
- Postoperative hemoglobin <8 g/dL occurred in 11.3% of the carbetocin group and 12.0% of the oxytocin group (p=0.981).
Limitations
- Observational, non-randomized study design.
- No statistically significant differences in primary or secondary outcomes.
- Sample size of 300 may limit generalizability.
- Short follow-up period of 24 hours.