[Serum placental lactogen in late pregnancy and its relation to placental villous surface and to placental maturation (author's transl)].

The placentas of ninety-six pregnancies supervised by measurements of human placental lactogen (HPL) were examined. The histometrically determined placental villous surface and the degree of maturation of the villous tissue were compared to HPL-values in late pregnancy and to the weight of the newborn. The production of HPL is dependent on the extent of the syncytiotrophoblast surface area and, in addition, is modulated by the grade of differentiation of the chorionic epithelium. Placental villi with abnormalities of maturation apparently synthesize more HPL than villi of normal maturation.