[The ratio birth-weight, placental weight and the term of delivery. A contribution to the problem of a relative placental insufficiency in late pregnancy (author's transl)].

It is suggested, that a relative placental insufficiency in late pregnancy is one of the releasing factors of childbirth. Under this assumption 1027 deliveries in term pregnancy (266th-294th day of pregnancy) were inquired on the interrelationship between the ratio brith-weight: placental-weight and the duration of pregnancy. The average birth-weight increases slighly but significantly with the duration of pregnancy just as the average placental-weight. The average ratio birth-weight: placental-weight decreases significantly: The more unfavorable the ratio birth-weight: placental-weight is, the shorter remains the fetus in utero. This underlines the assumption of a relative placental insufficiency as one of the releasing factors of childbirth.