Although a fetus is relatively protected in its mother's womb, a number of different toxins can harm the fetus. These include lead, mercury, glycol ethers, and many other substances. How do toxins usually reach the developing fetus

Although the blood of the fetus and the mother does not mix, Simple diffusion across the membrane of the placenta occurs. And since diffusion is the movement of ions and gaseous molecules across the membrane from the higher concentration of the mother blood to the lower concentration of the fetus, toxic chemical are conveyed across.,