Trophoblast is a specialized type of cell that plays an important role in pregnancy. It is derived from the blastocyst, which forms during early stages of embryonic development. The trophoblast cells surround and attach to the developing egg (ovum) after fertilization, forming the outer layer of the placenta. These cells are responsible for providing nutrients and oxygen to the growing fetus through the mother's bloodstream. They also help in the development of the fetal organs and hormone production during pregnancy. In some cases, abnormalities with trophoblast cells can lead to complications such as miscarriage or ectopic pregnancy.