Twin Births (Archived)

Excerpt

Twin births account for just over 3% of live births and 97% of multiple births in the United States. In the absence of assisted reproductive technology, dizygotic twins are much more common than monozygotic twins and account for 70% of all twin gestations. It is imperative to determine as early as possible in the pregnancy both the chorionicity (number of placentas) and anmionicity (number of amniotic sacs) of every twin pregnancy, as this is directly related to the incidence of complications, with monochorionic twin pregnancies.

Whereas the instance of dizygotic twins is variable in different populations, the prevalence of monozygotic twinning is globally constant at 3 to 5 per thousand births. NEED REFERENCE HERE Except for post-term pregnancy and fetal macrosomia, almost all pregnancy-related risks to both the pregnant patient and the fetuses are exaggerated, accounting for a large percentage of costs to the healthcare system. Guidelines have been established for antenatal surveillance and management of twin pregnancies to improve obstetrical care and decrease perinatal complications.