LOG IN
Baby Registry Finder
First TrimesterSecond TrimesterThird TrimesterPregnancy week by weekPregnancy showersBest of baby list
Toddler Month by Month
profile picture of Excerpted from The Baby Bump, Twins and Triplets Edition
Excerpted from The Baby Bump, Twins and Triplets Edition

Monochorionic Monoamniotic Twins?

The doctor isn't seeing a dividing line between the twins. What does that mean?

Some twins learn to share at a very young age. The majority of identical twins will share the same placenta but have separate amniotic sacs (monochorionic diamniotic), although a smaller percentage of identicals have their own of each one (dichorionic diamniotic). When there’s sharing involved, there’s a higher risk of complications, so you’ll likely be getting some extra attention from your doctor, and will almost definitely be referred to a maternal-fetal medicine specialist. One serious potential complication is twin-to-twin transfusion syndrome, where one twin gets too much blood and nutrients while the other doesn’t get enough. It’s still a relatively rare occurrence, but if your twins are sharing a placenta, let’s just say you’ll become very familiar with the magazines in her waiting room.

Plus more from The Bump:

Important questions to ask if having twins.

Are multiple pregnancies riskier than single pregnancies?

Vanishing Twins syndrome.