[Distribution of obstetrical and postnatal risk-factors in 400 randomly selected newborns. A study using Prechtl's concept of optimal conditions (author's transl)].

: The distribution of obstetrical and postnatal risk-factors in a population of 400 newborns was investigated. For documentation, an extended list of Prechtl's list of optimal obstetric conditions was used. The newborns had been selected randomly from two populations, born 1972 in two different hospitals (County hospital, University hospital). The reduction of optimal conditions was calculated by percentiles. It was found that the number -3 (of 52 items, representing full optimal conditions) defined the 10th percentile of the population; number -5 the median, and number -10 the 90th percentile. In addition, percentiles were calculated regarding the history of the mother and the history of the infant respectively. Using the distribution of reduced obstetrical and postnatal optimal conditions allows to compare the history of a single newborn or the histories of a population of newborns with defined problems. Newborns with rather low negative numbers of reduced optimal conditions are at lower risk regarding their psychomotor development wheras newborns with high negative numbers carry a much higher irsk in this respect.