Presentation
Review of pregnancy. 14 weeks and 6 days gestational age.
Patient Data

Monochorionic monoamniotic twin pregnancy (note entangled umbilical cords).
Twin 1 with anencephaly; no other morphologic abnormality is seen.
Twin 2 is morphologically normal with biometry concordant with dates.
Posterior placenta, closed cervix.
Case Discussion
Monochorionic, monoamniotic twin pregnancy. One twin with anencephaly and the other twin normal.
Laser cord ligation was offered to the patient at the time of examination. Pregnancy outcome, however, is not known.
Twin pregnancy is associated with a higher rate of non-syndromic anomalies than singleton pregnancy, and this is particularly notable in monochorionic twins.