Investigation of Foetal Mortality associated with Placenta Praevia

It is well known that a considerable part of the foetal mortality in placenta praevia is attributable to prematurity, which is usually assessed on the basis of weight. The low weight is at least partly explained by the short gestation, but the possibility that it also results from retardation of foetal growth deserves attention. The decidua of the lower uterine segment is believed to be less vascular than that of the upper segment, and, although placentae attached to the lower segment are said to be larger than normal (Colmeiro-Laforet, 1953), it is not known whether this hypertrophy is sufficient to satisfy the demands of the foetus. In this communi cation we inquire to what extent low birth weight accounts for the high foetal mortality in placenta praevia and whether the low weight is wholly attributable to early delivery, or is also partly due to retardation of foetal growth. The data assembled for this purpose also throw some light on the effect on foetal mortality of the modern tendency to adopt expectant methods of treatment. These methods were advocated by Macafee (1945) and Johnson (1945) in recognition of the high risk of foetal death associated with early delivery, and their observation that prolongation of pregnancy reduced the risks of the foetus without increasing those of the mother has been confirmed by others (Mills, 1948; Beilly, Greenberg, Aaron, and Peck, 1952). Examination of the influence of expectant treatment is complicated by the fact that during the last decade there have been other changes in the management of these cases. There has been an increasing tendency to treat placenta praevia, even the less severe types, by Caesarean section, and to avoid resort to hydrostatic bags, Willett's forceps, and version in cases delivered vaginally. We have no information about the effect of changes in treatment on maternal mortality. The frequency of maternal death in placenta praevia is now so low that a very large series of cases would be required for this purpose.