So we saw that active immunity can be acquired naturally or artificially. And so far we discussed the artificial process by which we gained passive immunity. So we actually synthesize those antibodies in a lab. Now, it turns out that we also have a natural way to obtain passive immunity and this takes place in a woman when a woman is pregnant with a child. So passive immunity can also be developed naturally. Pregnant women give their developing fetus passive immunity by producing specific antibodies known as immunoglobulin g. And immunoglobulins g are small enough to actually pass across the placental membrane and into the blood found inside our fetus.