The objectives of this research proposal are to develop further and to utilize evolving methods of quantifying placental function in a variety of normal and abnormal pregnancies as well as after pharmacologic manipulations of these pregnancies. By applying kinetic measurements of utero-placental metabolism, dynamic tests of placental function have been devised which take advantage of the fact that the placenta is an incomplete endocrine organ. Specifically, by determining the rate of utilization of a maternal plasma prehormone and then measuring the extent to which it is uniquely and irreversibly converted into an estrogenic compound within the placenta, a dynamic assessment of utero-placental function is possible. By employing a dynamic test of utero-placental function in contrast to the presently utilized determinations of static concentrations of placental hormones in various biologic fluids, it is hoped that this approach will circumvent the inherent hazards of interpretation of static measurements. With the utilization of such an approach, alteration in the kinetics of utero-placental function which result from physiologic abberations, various pathologic situations of pregnancy and finally pharmacologic intervention in normal and abnormal pregnancies may be assessed. Through the quantitative assessment of such factors that affect placental function either favorably or unfavorably, a rational scientific approach may be used to improve the intrauterine environment of the fetus. Additionally, it is hoped that with such a scientific approach rather than an intuitive or empiric approach that significant insight will be gained into the pathophysiology of such disease processes as hypertension of pregnancy, fetal intrauterine growth retardation, diabetes mellitus, and other disease processes which place the fetus at risk.