This chapter talks about the historical epidemiology of maternal mortality, the distribution and determinants of maternal mortality in England and Wales at nineteenth and twentieth centuries. In fact, the population at risk is not all women of childbearing age; it is only women during pregnancy, labor, or the puerperium. Maternal mortality has to be measured in terms of births, not total population. Work by R. Schofield suggests that the maternal mortality rate in England probably fell from about 100 per 10,000 births during 1700- 50 to around 80 during 1750-1800 and to between 50 and 60 in the first half of the nineteenth century. Three conditions, puerperal sepsis, toxemia, and hemorrhage, caused the majority of maternal deaths throughout the developed world from the mid-nineteenth century. Unlike deaths from septic abortion, those from puerperal fever were largely preventable. The risk of puerperal infection was greater because of the prevalence of the organism known as the Bhemolytic streptococcus.