The placenta occasionally takes a form in which it comprises several distinct parts connected by blood vessels. The parts, called lobes, may number two, three, four, or more. Such placentas are described as bilobed/bilobular/bipartite, trilobed/trilobular/tripartite, and so on. If there is a clearly discernible main lobe and auxiliary lobe, the latter is called a succenturiate placenta. Sometimes the blood vessels connecting the lobes get in the way of fetal presentation during labor, which is called vasa previa.
the placenta occasionally takes a form in which it comprises several distinct parts connected by blood vessels the parts called lobes may number two three four or more such placentas are described as bilobed/bilobular/bipartite trilobed/trilobular/tripartite and so on if there is a clearly discernible main lobe and auxiliary lobe the latter is called a succenturiate placenta sometimes the blood vessels connecting the lobes get in the way of fetal presentation during labor which is called vasa previa