[Relation between placental morphometry and fetal growth].

Forty-eight placentae of full term infants, 21 placentae from appropriate for gestational age infants (AGA) and 27 placentae from small for gestational age infants (SGA) were measured by morphometric technic using the automatic image analyzer, in order to find out the extent of fetomaternal exchange which determines the transfer of oxygen and nutrition from mother to fetus and fetal growth. The results of measurement correlated well both with infant birth weight and placental weight. They demonstrated striking quantitative differences when the placentae of SGA were compared with those of AGA. The placenta weights in the group of SGA were notably less than those in the group of AGA. It seems that low birth weight relates to low functional tissue mass of placenta. This reduction of functional tissue is accompanied by diminution of the area for exchange between mother and fetus, both at the villous surface area and at fetal capillary surface area. Thus, the ability of transferring oxygen and nutrition from mother to fetus is curtailed. The results show that the rate of fetal growth is limited by placental function as well as its weight.