Calcium as a Uterotonic: Cheap, Available, and (Maybe) Effective?

( Int J Obstet Anesth 2025 Aug:63:104711. doi:10.1016/j.ijoa.2025.104711) For decades, calcium’s role in initiating contraction across smooth, skeletal, and cardiac muscle has been well established, yet only recently has interest grown around its potential as a prophylactic or therapeutic uterotonic. In the above article, Abirami and colleagues describe a randomized, placebo-controlled trial involving 367 intrapartum cesarean deliveries (CDs) that examined whether administering 1 g of intravenous calcium gluconate (CaGlu) could improve uterine tone and reduce postpartum hemorrhage (PPH). Although the primary endpoint, obstetrician-assessed uterine tone, did not differ significantly between groups, patients who received CaGlu required fewer second-line uterotonics and experienced slightly lower quantitative blood loss. While the study lacked statistical power to evaluate transfusion outcomes, only one patient in the CaGlu arm and three in the placebo arm received blood products.