Collection of fetal blood for stem cell research and therapy

Stem cell research has generated novel therapeutic opportunities at the expense of new ethical and legal problems. Its promoters recommended early clamping of the umbilical cord to maximize the amount of acquired fetal blood. Fear has been expressed, therefore, that the donor could be compromised by this approach. Actually, the problem is more complex than generally assumed. In certain clinical situations the neonate may benefit from or become harmed by additional blood volume. Gravity influences the direction of umbilical blood flow and, thus the consequences of early or delayed cord clamping. Therefore, vaginal birth promotes blood flow from the placenta to the fetus, whereas delivery by cesarean section usually has the opposite effect. Largely ignored in the course of the relevant debates, the above facts require consideration. The controversy may be beneficial in the long run by drawing attention to this relatively neglected aspect of perinatal medicine.