[Multifactorial disturbances and compensatory phenomena in the materno-fetal unit (author's transl)].

Clinical and laboratory data as well as morphological placenta findings of approximately 7 000 pregnancies recorded in a program of the German Research Association (DFG): "Course of pregnancy and development of the newborn" are examined for statistically significant correlations. It could be shown that there is a correlation between haemoglobin-level during pregnancy and maturation of the placenta villi. Low maternal haemoglobin frequently coexists with complete villous maturation. The same interaction is true for placental size or weight and maternal haemoglobin. Small placentas show a--sometimes precocious--complete villous maturation, whereas placentas with greater volume still possess immature villi at term. This finding is different in combination with placental infarcts, which lead to a complete maturation of persistent villi, especially, if the maternal haemoglobin shows low values at the same time. The combination of the factors: low maternal haemoglobin and small placental insertion area or insufficient placental maturation and low maternal haemoglobin lead with statistical significance to a high frequency of babies with low birth weight in relation to the duration of pregnancy. This is not the case, if one of the two factors involved shows favorable characteristics (morphological findings in the placenta with good functional aspects--maturity, insertion area--and low haemoglobin or high haemoglobin in combination with favorable placenta findings). Summing up the results demonstrate that interactions between single factors of the materno-fetal transfer-system constitute a basic developmental principle.