A molar pregnancy, or as it is known medically, a hydatidiform mole, is a pregnancy in which the placenta develops into a mass of fluid-filled sacs that resemble clusters of tiny grapes. It grows in an uncontrolled fashion to fill the womb. It occurs in about 1 in 700 pregnancies. Sadly a molar pregnancy is destined not to develop normally and becomes early pregnancy loss. This means there is no possibility that your pregnancy can survive. There are two types of molar pregnancy: a complete and a partial hydatidiform mole.