Bleeding, and what counts as hemorrhage
Cesarean bleeds more than vaginal birth. Sometimes much more.
Postpartum hemorrhage is currently defined as cumulative blood loss of 1,000 mL or more, or blood loss with signs of low blood volume, within 24 hours of birth, regardless of how the baby was delivered.
Bleeding is managed with uterine massage, medications that contract the uterus, stitches, balloons that tamponade the uterus from inside, and, if those fail, surgery.
Tranexamic acid can reduce measured blood loss. In a trial of 4,153 women, the combined outcome of blood loss over 1,000 mL or transfusion occurred in 26.7% with tranexamic acid and 31.6% with placebo. However, transfusion rates themselves were not significantly reduced, and blood clot events were numerically higher with tranexamic acid (0.4% versus 0.1%, not statistically significant). This is an honest example of a treatment whose benefit is narrower than it first appears.