[Frequency of breech presentation during pregnancy and on full term (author's transl)].

The causes underlying the relationship between breech presentation and premature birth were studied, with reference to the premature birth discussion which has assumed sizeable dimensions in the obstetric community. -- An evaluation of 785 ultrasonographic findings from pregnant women has shown breech presentation to be just as frequent as vertex presentation up to the 24th week of pregnancy. The former, consequently, should be considered as physiological. The frequency of breech presentation was found to go down continuously only beyond the 24th week and to drop below five per cent, after the 35th week of pregnancy to reach eventually the figure usually recorded at birth. These observations were found to be in good agreement with what has been reported by other authors. -- The authors of this paper were struck by surprise, when they found that the breech presentation figure, in the context of 997 premature births, was, with high significance, below the level usually recordable from unimplanted pregnancy. -- The above findings are discussed in great detail. Preliminary suggestions are made regarding possible interpretations. Yet, further target-oriented studies are required.