| Multiple gestations, or any pregnancy that results in the development of more than one fetus, is considered high risk. Multiple gestations occur more frequently with fertility drugs.
There are two types of multiple gestations. One type is known as monozygotic, because the zygote divides and results in development of identical fetuses that may or may not share the same amnion. Conjoined, or Siamese twins, occur only in the case of monozygotic twin pregnancies. |