How did hand and clothing disinfection reduce puerperal fever?

In the 19th century, puerperal fever was a leading cause of maternal mortality in hospitals. Physicians like Ignaz Semmelweis observed that mortality rates were significantly higher in clinics where medical students performed examinations after coming directly from the dissecting room compared to clinics staffed by midwives.1

Semmelweis hypothesized that these students were carrying infectious material—which he termed "cadaverous particles"—from autopsies to healthy mothers during labor. To address this, he mandated that students and staff wash their hands in a solution of chlorinated lime before each examination. Additionally, practitioners like Oliver Wendell Holmes and others advocated for the disinfection of both hands and clothing to prevent the transmission of pathogens.12

These antisepsis measures effectively broke the chain of transmission, leading to a dramatic decline in maternal deaths. By removing these contaminants, medical professionals prevented the introduction of bacteria into the reproductive tract, thereby reducing the incidence of septicemia and other fatal complications associated with childbirth.123