How did Ignaz Semmelweis reduce cases of puerperal fever after childbirth?

Ignaz Semmelweis, a Hungarian physician working in a Vienna obstetric clinic during the 1840s, significantly reduced mortality rates from puerperal fever by identifying its infectious nature and introducing antisepsis into medical practice.

Semmelweis observed that death rates were significantly higher in clinics where medical students—who often came directly from performing autopsies in the dissecting room—examined patients, compared to clinics staffed by midwives. He hypothesized that these students were carrying infectious material from deceased mothers to healthy ones during labor. To combat this, he ordered students and staff to wash their hands in a solution of chlorinated lime before every examination.

This simple but revolutionary intervention led to a dramatic drop in mortality rates, falling from 18.27 percent to 1.27 percent in his division. His work laid the foundation for modern infection control, eventually earning him recognition as a pioneer in the field, despite facing significant professional resistance and hostility during his lifetime.12