Historical mortality rates of puerperal fever

An 1841 account of epidemic childbed fever states that insofar as existing historical documents permit one to judge, childbed fever is a modern disease. The cases reported by Hippocrates that are generally identified as such are not puerperal fever. There are only examples of bilious fever, then common, which among maternity patients was no different from its appearance among non-maternity patients or men; Hippocrates himself never identified it as a separate and distinguishable disease.[1]

Hôtel Dieu in Paris, about ad 1500. The priest on the right is issuing the last sacraments, while a nun administers to the patient on the left. Patients often slept two, three and even four to a bed

We encounter the first, as yet unclear indication of childbed fever in the second half of the 17th century at the Hôtel-Dieu in Paris. Phillipe Peu relates that mortality among the newly delivered was very great and greater in certain seasons than others. The year 1664 was particularly devastating.[1]

Another account states that the lower abdominal infection, la fièvre puerpérale, had raged every winter since 1774 among the maternity patients of the Hôtel-Dieu, and that often as many as 7 of every 12 patients suffered from it.[2]

For the relatively small maternity clinic at Würzburg in Germany, Franz Kiwisch von Rotterau reported 27 deaths from 102 patients (26.5%) cared for during one year, much higher than the Viennese hospital. Semmelweis explained this from the need in small hospitals to use every patient as teaching material. In contrast, "in Vienna there is such an excess of teaching material that hundreds of individuals are not used for teaching and thus are not infected".[3]

There are various inconsistencies in the datasets reported by Semmelweis and provided below. Inconsistencies exist for instance in reported yearly rates, and monthly rates (if aggregated to yearly basis). One of the causes may be that Semmelweis used different sources. He points out several times that actual mortality rates were higher than reported ones, because during childbed fever epidemics, the maternity ward was overwhelmed with dying women, who were then transferred to the general hospital, and therefore not registered at the maternity ward, when dying.[4] Some women were also released from the maternity ward, either healthy or not so healthy, only to be readmitted to the general hospital when symptoms appeared or worsened. See also a similar underreporting practice at the Charité in Berlin, Joseph Hermann Schmidt.

There were two maternity clinics at the Vienna General Hospital. Semmelweis is not always specific, if the numbers are for both clinics, or for his own clinic only. The figures presented below are exactly as reported in (the 1983 translation by Carter of) Semmelweis' 1861 publication.

There are also at times minor arithmetical errors in his computed rates; for this reason all rates on this page are computed.

The table below shows monthly incidence rates from 1841–1849, Semmelweis' handwashing policy was implemented from June 1847 to February 1849.

Puerperal fever monthly mortality rates at Vienna Maternity Institution 1841–1849. Rates drop when implementing handwash

From his theory of decaying matter on the hands of examining physicians as a cause for childbed fever he was able to explain other features in the dataset, for instance why mortality rates were remarkably higher during winter than summer, because of increased student activity and scheduled autopsies immediately before the rounds at the maternity clinic. He writes:

The prevailing opinion is that winter is the season most conducive to outbreaks of childbed fever. This is explained by the different activities of those who visit the maternity hospital. These activities are determined by the season. After the long vacation in August and September, students resume their studies, including obstetrics, with renewed diligence. In winter the influx of students into the maternity hospital is so great that individuals must wait weeks and even months for their turn to study. In summer, during vacation, half or even two-thirds of the places are vacant. In winter, the pathological and forensic autopsies and the medical and surgical wards are visited industriously by those who also visit the maternity hospital. In summer, the diligence is noticeably less. The charming surroundings of Vienna are more attractive than the reeking morgue or the sultry wards of the hospital.

In winter the assistant of obstetrics holds practical operative exercises on cadavers before the afternoon rounds at the maternity ward at four o'clock, because in the mornings students are otherwise engaged, and following the afternoon rounds, at five o'clock, it is already too dark. In summer the heat is too oppressive before the afternoon visit, and the operative exercises are held in the evening following afternoon rounds.[6]

He was able to explain additional features:

The assistant of the first clinic seldom visited the morgue in the months of December 1846 and January, February, and March 1847. The students followed his example. The opportunity for them to contaminate their hands with cadaverous particles was thereby greatly reduced. Restricting examinations to the minimum also reduced the opportunity for the genitals of patients to be touched by contaminated hands. For these reasons, mortality in the first clinic was reduced during these months.

I had Carl von Rokitansky's permission to dissect all female corpses, including those not already set aside for autopsy, in order to correlate the results of my examinations with autopsies. I devoted nearly every morning before the professor's rounds in the obstetrical clinic to these studies. On 20 March 1847, I reassumed the position of assistant in the first clinic. Early that morning I conducted my gynecological studies in the morgue. I then went to the labor room and began to examine all the patients, as my predecessors and I were obliged to do, so that I could report on each patient during the professor's morning rounds. My hands, contaminated by cadaverous particles, were thereby brought into contact with the genitals of so many women in labor that in April, from 312 deliveries, there were 57 deaths (18.3 percent).[7] Only God knows the number of patients who went prematurely to their graves because of me. I have examined corpses to an extent equaled by few other obstetricians.[8]

He was also able to explain why women with extended dilation invariably died: "Infection occurs most often during dilation. [...] ..it is frequently necessary to penetrate the uterus in manual examination to determine the location and position of the fetus. Thus, before chlorine washings, almost every patient whose period dilation was extended died of childbed fever."[9]

A second clinic was started in 1833 because of the large number of women being admitted to the maternity ward. Medical students and midwife students undertook their studies at both clinics. In 1841 however, these two groups were separated. Thereafter, medical students attended the first clinic only, and midwife students attended the second clinic only. Joseph Späth was professor at the second clinic.

Puerperal fever yearly mortality rates at Vienna Maternity Institution 1833–1858 for first and second obstetrical clinics. Period with Semmelweis' handwashing policy marked with red rectangle

Semmelweis seeks to demonstrate that the advent of pathological anatomy, and consequently the increase in autopsies, is correlated to the incidence of childbed fever. From 1789–1822 professor Johann Lucas Boër was assigned the teaching post at the maternity ward, however he left the post discouraged of what was then regarded as an enormous mortality rate. He was succeeded by professor Johann Klein who reformed obstetrics to an anatomical orientation emphasizing the value of pathological autopsies. Mortality rates jump markedly.

Yearly puerperal fever mortality rates 1784–1849 in Wien and Dublin. Semmelweis seeks to demonstrate that the advent of pathological anatomy in Wien in 1823 is correlated to the incidence of childbed fever. See section below for data for Dublin.

The mortality rate for newborn infants was also higher in the first clinic.

• Semmelweis, Ignaz (1983) [1861]. Etiology, Concept and Prophylaxis of Childbed Fever. Translated by Carter, K. Codell. University of Wisconsin Press. ISBN 0-299-09364-6.