[Parameters for the evaluation of perinatal well-being: fetal and placental weight, placental and fetal ratio].

Authors study fetal and placental weight during last weeks of gestation, as well as their correlations. At the end of gestation fetus grows more than placenta until the 40th week. From this moment, fetal growth slows and the placenta enlarges in order to maintain fetal homeostasis. Both ratios between placental and fetal weight are useful in evaluating parameters to show alterations of fetal and placental growth.