reviewed the database and medical records of 857 twin pregnancies, including 140 monochorionic twins. Nineteen monochorionic-monoamniotic twin pregnancies were detected, four of which were complicated by conjoined twins.Results: Of these 4 cases, 2 were complicated by thoracopagus and one had thoraco-omphalopagus; these three cases underwent termination at 16, 11, and 19 weeks gestation, respectively. The last case was diagnosed as a pygopagus tetrapus parasitic twin at 28 weeks gestation. The family decided to continue the pregnancy, and achieved a successful outcome with elective surgery postpartum. Conclusion:Conjoined twins are an uncommon and complex complication of monozygotic gestations, which is associated with high perinatal mortality. The early prenatal diagnosis of conjoined twins allows improved counseling about the management options, including maintenance of pregnancy with surgery after delivery or termination of pregnancy. (J Turkish-German Gynecol Assoc 2010; 11: 174-7) Key words: Conjoined twins, prenatal diagnosis Received: 22 December, 2009 Accepted: 11 February, 2010 Amaç: Prenatal olarak tanısı konmuş yapışık ikiz olgularında bulguların değerlendirilmesi. Gereç ve Abstract ÖzetOriginal Investigation 174