The Midrash teaches that an infant is circumcised on the eighth day, not earlier, because Hashem in His mercy delayed the mitzva until the eighth day until the baby would have strength to withstand the procedure.
Remarkably, in recent years, modern science has uncovered a fascinating insight that aligns perfectly with this ancient wisdom. One of the body’s primary clotting agents is a protein called prothrombin. In the first few days after birth, the amount of blood clotting agents is so low that even a minor cut could pose a serious threat to the infant’s life. However, by the eighth day of life, these levels not only reach their normal range but actually peak beyond it. This surge ensures that the baby's blood can clot effectively, making it possible to perform circumcision without concern for excessive bleeding.
