What is it?

Conjoined twinning is a rare complication where genetically identical twins are abnormally fused together at one or more body sites.

How common is it?

Conjoined twins are extraordinarily rare.

How is it managed?

Conjoined twins are diagnosed by ultrasound, and the condition can be further characterized with the use of fetal echocardiography and MRI. Affected twins are also at high risk for congenital anomalies. In ongoing pregnancies, cesarean delivery is generally recommended.


The prognosis for conjoined twin pregnancies is largely dependent upon which body parts and organs are shared. Some conjoined twins may be candidates for operations after birth that attempt to separate the twins, although survival is not always possible. In many cases, surgical separation may not be possible.