Complications of Monochorionicity

Monochorionic describes a pregnancy in which more than one fetus share a placenta. Several conditions are unique to monochorionic fetuses, some of which result in fetal-fetal vital conflicts. This paper reviews conditions unique to monochorionicity, including discordant anomaly, risk of cotwin stroke or death after co-twin demise, twin-twin transfusion syndrome, selective fetal growth restriction, twin anemia-polycythemia sequence, and twin reversed arterial perfusion sequence. Treatment options available in mainstream medical literature are listed. The author offers preliminary comments on the acceptability of treatments within Catholic teaching, including a novel discussion of cord coagulation of a dying twin to prevent the co-twin’s neurological injury or death. This is the second in a two-part paper.