Pregnant rats were given subcutaneous injections of radioactive aluminum, which reached the embryo’s brain in just a couple of days. After the birth, the aluminum continued to accumulate in the brain, now passed on through the breast milk.
High level of aluminum in mother’s hair is associated with congenital heart defects of the child.
95% of women who gave birth had aluminum found in the placenta, 81% had it in the placental membrane, 46% - in the umbilical cord. This goes to the question of vaccinating pregnant women.