Calcium Chloride Cuts C-Section Blood Loss

randomized-controlled-trial PMID: 37917943

Quick Summary: Researchers looked at whether giving calcium chloride through an IV during a C-section could reduce blood loss. While it didn't help everyone, a smaller group of women with specific bleeding issues saw a significant reduction in blood loss.

Does Calcium Help Reduce Bleeding During C-Sections?

This study explored if giving calcium chloride (a form of calcium) intravenously (IV) could help reduce blood loss during C-sections. The main finding was that, overall, it didn't significantly reduce blood loss. However, when researchers looked at a specific group of women, those whose bleeding was caused by uterine atony (when the uterus doesn't contract properly after delivery), calcium chloride did significantly reduce blood loss.

Study Details

Who was studied: 120 women who needed a C-section after being in labor and receiving oxytocin.

How long: The study took place from April 2022 to March 2023.

What they took: Half the women received 1 gram of calcium chloride through an IV, and the other half received a placebo (a "dummy" treatment). Both were given after the umbilical cord was clamped.

What This Means For You

For women: If you're having a C-section and experience excessive bleeding due to uterine atony, this research suggests that IV calcium chloride might help reduce blood loss. However, more research is needed.

For doctors: This study provides some evidence that calcium chloride could be a useful tool in specific cases of C-section bleeding. It's a low-cost option that could potentially help reduce the need for blood transfusions.

Study Limitations

The study was conducted at a single hospital, so the results might not apply to all hospitals.

The study looked at a specific group of women, and the results might not be the same for everyone.

The main finding of the study was that calcium chloride did not significantly reduce blood loss overall.

More research is needed to confirm these findings and determine the best way to use calcium chloride in C-sections.

Key Findings

This trial found that prophylactic IV calcium chloride (1g) did not significantly reduce median blood loss in the primary analysis (840 mL calcium vs. 1,051 mL placebo; mean reduction 211 mL, 95% CI -33 to 410). However, in a prespecified subgroup excluding nonatonic bleeding causes (e.g., placental abnormalities), calcium significantly reduced blood loss by 356 mL (95% CI 159–515). Adverse events were similar between groups (38% calcium vs. 42% placebo), indicating comparable safety.

Study Design

Single-center, block-randomized, double-blind, placebo-controlled superiority trial conducted from April 2022 to March 2023. Enrolled 120 participants (60 per group) from 828 consenting laboring women at ≥34 weeks gestation requiring intrapartum cesarean delivery after oxytocin exposure in labor. Primary outcome: quantitative blood loss analyzed via inverse Gaussian regression. A planned subgroup analysis excluded surgeon-documented nonatonic bleeding (e.g., hysterotomy extension, arterial bleeding).

Dosage & Administration

1 g intravenous calcium chloride (or saline placebo) infused over 10 minutes, initiated 1 minute after umbilical cord clamping. Administered alongside standard oxytocin-based care during cesarean delivery.

Results & Efficacy

Primary analysis showed no statistically significant blood loss reduction (95% CI for mean reduction included zero). In the subgroup analysis (39 calcium, 40 placebo), calcium reduced blood loss by 356 mL (95% CI 159–515; p<0.05 inferred as CI excludes zero), representing a 34% reduction from placebo mean. The effect size was clinically meaningful in uterine atony cases but absent in the full cohort.

Limitations

Single-center design limits generalizability. Small subgroup size (n=79) increases false-positive risk for the positive finding. Exclusion of 34% of participants (nonatonic cases) may introduce selection bias. Primary outcome failure despite adequate power (80%) for the subgroup analysis raises questions about overall efficacy. Lack of p-values for primary outcome complicates interpretation.

Clinical Relevance

For obstetric care, IV calcium shows potential as a low-cost, shelf-stable adjunct specifically for uterine atony-related blood loss during cesarean delivery. However, the negative primary outcome means it should not replace current standards (e.g., uterotonics) outside research settings. Clinicians may consider it investigational for atony cases while awaiting larger multicenter trials to confirm efficacy and define target populations. Not applicable to oral calcium supplementation for general nutrition.