Case Reports in Women ' s Health 3 D Assisted Prenatal Sonographic Diagnosis of Dicephalic Conjoined Twins and Subsequent Planned Vaginal Delivery ☆ , ☆ ☆

Conjoined twinning is a rare occurrencewith an incidence of about 1 in 50,000 pregnancies, 60% of which result in stillbirth [1]. There is an approximate 2–3:1 female to male predominance [1]. The classification of conjoined twins is complex, but is usually based on degree and anatomic location of the fusion [2]. Parapagus twins always share a conjoined pelvis with one or two sacrums and a single symphysis [2]. Dicephalic parapagus twins share a common thorax and account for approximately 3.7% of all conjoined twins [1].