The authors introduce the methodology of planning, empiric execution and a model of analysis in perinatal health. Live births from nosocomical deliveries was studied at Ribeirão Preto's neighborhood, Brazil, from June 1978 to May 1979. Parturient women from 8 maternities were interviewed and information was obtained regarding parents, family income, pregnancy, delivery (including medical care to newborn), children deaths, race and human reproduction. It is showed, in detail, the stages of project execution. The model of social class used and its operations research a basic point in the analysis.