THERE are many situations in obstetrics in which maternal history, symptoms or signs may alert the obstetrician that all may not be well with the uterine contents, but the wisest management may be apparent only in retrospect so long as the condition of the fetus or placenta can be expressed only in terms of statistical probability or undecided possibilities.The epitome of this situation is seen in the Rhsensitized patient. The detection of an isoimmune antibody poses more problems than it solves and must be regarded as the beginning rather than the end of adequate antenatal examination in hemolytic disease. . . .