Nataly’s Knowledge Hub

Questions, evidence and clinical experience on postpartum hemorrhage and maternal health.

Why is blood loss so hard to estimate after birth?

Quick answer

Because it is almost always judged by eye, and the human eye is bad at this. According to the 2025 Cochrane review of diagnostic tests for postpartum hemorrhage, visual estimation detects only 48% of cases at vaginal birth. Blood is diluted, absorbed, and spread across several surfaces at once.