We present the case of tapered umbilical cords in monoamniotic monocorial twins with late abortion as an outcome. A pregnant woman at the age of 38 had healthy course of her second pregnancy. In the 9th week of gestation, an monoamniotic monocorionic pregnancy was diagnosed by ultrasound. Early amniocentesis was done due to the older age of a mother. During the procedure an enlargement of the umbilical cord was discovered, and the wrapping of the two umbilical cords. Mosaic trisomy of the 21st chromosome was proved. In the 19 w + 3 d gest., negative heart beats were detected for both of fetuses. The induction of abortion was initiated by prostaglandin vaginal gel (dinoprost). There were no signs of maceration, the weights were 230 and 190 grams, with increased and wrapped umbilical cords. The pathohistological fi nding confi rmed monochorionic-monoamniotic twin pregnancy with a long and tightly knit umbilical cord with complete blood fl ow obstruction and no signs of fetal malformalities. Also, there were no clinical signs of fetal transfusion syndrome. It is probably that the umbilical cord of the second twin was hypoplastic and with more complications
