Methods of prenatal determination of fetal maturity based on differentiation of the fetal skin during the last weeks of pregnancy

During the process of ‘maturation’ of the fetal skin, detachment of the layer of vernix caseosa takes place from the fetal epidermis into the amniotic fluid, in the course of the last weeks of pregnancy. This results in: (a) a change of the cytological image of the amniotic fluid followed by a considerable increase in the proportion of the keratinized epidermic cells, (b) a simultaneous increase in the turbidity of the amniotic fluid and (c) a parallel increase in the quantity of sediment which remains after centrifugation of the amniotic fluid. The data presented in this paper, measured in 87 samples of amniotic fluid from normal, eutrophic, uncomplicated pregnancies, indicate the difference between the values of the various parameters before and after the main detachment of the vernix caseosa. Since the fetal skin is the organ reflecting most accurately the general status of the fetal maturity at the end of pregnancy, we consider that an overall examination of findings from the amniotic fluid indicating the condition of the fetal skin supplies us with reliable results for making a prenatal prediction of the maturity status of the fetus.