Cardiac clinics are now part of the standing equipment of most obstetric services. While a general trend toward a more successful management of these cases is apparent, there is disagreement on almost every detail of the problem. This is partly because of insufficient individual experience and partly because statistical methods have been neglected in the analysis of collected data. Therefore the present study was undertaken for the purpose of gathering sufficient data on controversial issues, and of treating these data statistically. For the purpose of detailed study nearly 1,000 case reports were collected from the literature and, to a small extent (fifty), from the records of the St. Louis Maternity Hospital. 1 More than 300 of these cases were fatal. PUBLIC HEALTH ASPECTS It is difficult to learn the prevalence of rheumatic heart disease among pregnant women. It probably varies according to climate, race and social stratum. The recorded incidence