[Three-dimensional ultrasonography of monoamniotic twins]

A case of monoamniotic twins is described. Three-dimensional ultrasound scanning (3DUS) was used to visualise the fetuses lying in a single amniotic cavity. Entanglement of the umbilical cords with several knots was also visualised. The infants were delivered by elective caesarean section at 32 + 2 weeks with an uncomplicated postpartum course. Several knots found between the two umbilical cords, with separate placental insertion, were consistent with the ultrasound scan. We suggest that dedicated software solutions for volumetric ultrasound and knot analysis could contribute to a more precise description of the entanglement, which again would be a useful prognostic tool in the antenatal management and delivery of monoamniotic twins.