- monochorionic monoamniotic (MCMA) pregnancy: single amnion
- monochorionic diamniotic (MCDA) pregnancy: two amnions: much more common ~90%
As they are almost always monozygotic (except in extremely unusual cases), both the twins in a monochorionic twin pregnancy are of the same gender.
Pathological processes that occur almost exclusively in monochorionic pregnancies include:
- 1. Fetal Medicine for the MRCOG and Beyond. RCOG Press. ISBN:1906985367. Read it at Google Books - Find it at Amazon
- 2. Creasy RK, Resnik R, Iams JD. Maternal-fetal medicine, principles and practice. W B Saunders Co. (2004) ISBN:0721600042. Read it at Google Books - Find it at Amazon
- 3. Entezami M, Albig M, Knoll U et-al. Ultrasound Diagnosis of Fetal Anomalies. Thieme. (2003) ISBN:1588902129. Read it at Google Books - Find it at Amazon