Semmelweis's hypotheses: Almost 150 years since Ignàc Fülöp Semmelweis passed away

Abstract

Ignàc Fülöp Semmelweis (1818-1865) made a turnover in the history of hospital infections. His life's aim was to find the cause and to control high rate of mortality from puerperal fever. Semmelweis was one of the first scientists to use formal collecting of information and statistics to test his hypotheses. Using observation, he set several hypotheses. His first hypothesis indicated that the gender of the person doing delivery can cause different mortality rates from puerperal fever. Semmelweis soon abandoned this hypothesis which led to a different one - overcrowding increases the mortality rate of puerperal fever. With further studies he abandoned this hypothesis, too, and set another one. Did the fear of death and discomfort during examination and delivery done by men have the effect on mortality rates? He considered the delivery technique and introduced the use of lateral position for all deliveries, but mortality rate remained the same. Semmelweis noticed that women who delivered their child on the street had lower mortality rate than the women who delivered in hospital. At that time he got the idea that it was due to endemic disease. In the next several years, Semmelweis tried to verify several hypotheses: did the rough examinations done by medical students raise the mortality rate, did the orientation of the bed with respect to East, West, North, or South affect the mortality rate from puerperal fever due to cold wind from the north, did examinations performed by foreign medical students affect the mortality rate? None of these hypotheses were verified. Statistical analysis of the number of deliveries and mortality rates showed a lower mortality rate during December 1846 and January, February and March of 1847, which was later attributed to the lower rate of autopsies done by medical students who later did the examinations of women in labour. At that time Semmelweis came to another hypothesis: The cause of high mortality rate was something that could transfer on hands, which he called 'Poison from cadaver'. He soon announced the hypothesis of transferring these particles into the bloodstream by stabbing themselves during autopsies or surgeries and during vaginal examination done by medical students and doctors after they worked on cadavers. At the same time he noticed high mortality rates in the women who were examined at the same time as the women who had ulcers on their legs with pus. Considering the fact that he could not forbid medical students to do examinations on women in labour right after their pathology class on autopsies, he introduced the hand hygiene and disinfection with calcium-hypochlorite as a way of prophylaxis, which significantly decreased the mortality rate from puerperal fever. By doing this experiment Semmelweis proved his hypothesis that puerperal fever is caused by particles that spread from cadaver. The importance of Semmelweis's discovery remained unrecognized during his life. It was only after his death that he became known as 'savior of mothers'.