[Time sequence of risks. a new approach to weighting perinatal perils (author's transl)].

In the Munich area from 1975 to 1977 37.3% of 55089 women came to birth without any risk, 7.4% with anamnestic risks (i.e. existing before pregnancy), 12.1% with gestational risks acquired during pregnancy, 4,0% with anamnestic and gestational risks. In 17,0% risks were developed at first during delivery. 4.0% of the pregnant women had anamnestic and birth risks, 12.6% gestational and birth risks, and 5.5% anamnestic and gestational and birth risks. There were remarkable interrelationships between the combination of risks, obstetrical management and outcome (perinatal mortality and infant transferral rate as a crude measure of neonatal morbidity). Anamnestic risks are followed by gestational risks with a chance of 50%. If pregnancy began without risks the probability of gestational risks is approximately 33%. Some distinct anamnestic risks considerably contribute to cesarean section rate. Risks solely occurring during pregnancy have a rather low perinatal mortality (6%o compared to 2%o of riskfree pregnancies). The combination of gestational and birth risks increases perinatal mortality and neonatal morbidity by a factor of 10. This increase is due to some "mortgage-risks", i.e. impairments which are still present at birth. Among those risks conditions most often associated with threatening preterm delivery predominate. Pregnant women who develop such persisting risks should be transferred to a perinatal center.