For centuries, it was accepted that many mothers developed fever and died following childbirth. Puerperal fever, an illness that we now recognize is the result of a bacterial infection of the uterus following childbirth, had occurred at least since the time of Hippocrates (460–377 b.c.). In the 18^th century, when it became popular for women to deliver their babies in hospitals, the incidence of the disease rose to epidemic proportions. In Prussia between 1816 and 1875, over 363,600 women died of puerperal fever. In the middle of the 19^th century in the hospitals of Vienna, the major medical center of the world at that time, about one of every eight women died of puerperal fever following childbirth.

In 1841, Ignaz Semmelweis, a Hungarian, traveled to Vienna to study medicine. After finishing medical school, he became the first assistant to Professor Johann Klein at the Lying-in Hospital. There were two sections of the hospital. The first section was under the management of Professor Klein and the medical students. Midwives and midwifery students served the second section. Being an astute observer, Semmelweis soon noticed that the incidence of puerperal fever in the first section often rose as high as 18%, four times that in the second section. When he investigated the conditions in the two sections, they appeared to be the same except in terms of their management. Semmelweis was dismissed from his post when he implicated Professor Klein and the students in the spread of the disease, but he was reinstated a few months later when others intervened on his behalf.

Semmelweis recognized that disease symptoms that led to the death of a friend who had incurred a scalpel wound while doing an autopsy were similar to puerperal fever. He reasoned that the "poison" that killed his friend probably also contaminated the hands of the medical students who did autopsies. These students were transferring the "poison" from the cadavers to the women in childbirth. Midwives did not perform autopsies. Since this was before Pasteur and Koch established the germ theory of disease, Semmelweis had no way of knowing that the "poison" being transferred was probably Streptococcus pyogenes, a common cause of many infections, including puerperal fever. Those being autopsied had likely died of streptococcal disease as well. To test his hypothesis, Semmelweis instituted the practice of having physicians and students wash their hands with a solution of chloride of lime, a strong disinfectant, before attending their patients. The result was a drop in the incidence of puerperal fever to one-third its previous level. Instead of accepting these findings and the new techniques that Semmelweis employed, his colleagues in Vienna refused to accept responsibility for the deaths of so many patients. His work was so fiercely attacked that he was forced to leave Vienna and return to his native Hungary. There he was again able to use disinfection techniques to achieve a remarkable reduction in the number of deaths from puerperal fever.

Semmelweis became increasingly outspoken and bitter, finally becoming so deranged that he was confined to a mental institution. Ironically, he died one month later of a generalized infection similar to the kind that had killed his friend and the many women who had contracted puerperal fever following childbirth. The infection originated from a finger wound received before his confinement. Some said he deliberately infected himself from a cadaver while performing an autopsy.

The accomplishments of Ignaz Semmelweis would be the envy of today’s hospital epidemiologists. Without knowledge of microbiology or the germ theory of disease, he rigorously defined the affected population, located the source of the causative agent and its mode of transmission, and showed how to stop the spread of the disease.