It is important, early on in your pregnancy, to determine what type of multiple you are carrying. What matters is how many placentas and how many amniotic sacs are present. This is determined by ultrasound, so a plan of care can be initiated for a safe pregnancy and uneventful delivery.
There are three basic types of twins.
Dichorionic/Diamniotic(di/di) twins. In di/di twins, each twin has their own placenta and their own amniotic sac.
Monochorionic/Diamniotic (mo-di) twins. Mo/di twins share a placenta, but each baby has it’s own amniotic sac. Anytime babies share a placenta, they are at risk developing Twin-Twin Transfusion Syndrome, which means that the blood and nutrients flow from the placenta of one baby to the placenta of the other baby. Because of advanced monitoring and treatments available, these babies have a better chance of survival when discovered early via ultrasound.
Monochorionic/Monoamniotic (mo/mo) twins. This is least common type of twin and the highest risk type. They have one placenta and one amniotic sac. They have the same risk factors for TTTS as the mo/di twins have, but the difference here is that they share one amniotic sac and the umbilical cords can get tangled or compressed.
We will closely manage your pregnancy with your primary obstetrician and increase fetal monitoring and ultrasounds as your pregnancy progresses. There are many web sites to go to learn about pregnancy and twins.