Conjoined twins after intracytoplasmic sperm injection and transfer of a single day 2 embryo: case report.

Objective: To describe a case of conjoined twins after intracytoplasmic sperm injection (ICSI) and transfer of a single day 2 embryo.

Design: Case report.

Setting: University hospital.

Patient(s): A 30-year-old woman underwent ICSI with a transfer of a single day 2 embryo.

Intervention(s): Vaginal ultrasound examination was performed during early pregnancy.

Result(s): The diagnosis of conjoined twins was made by vaginal ultrasonography at 9 weeks' gestation. The conjoined fetuses were diagnosed as thoracopagus twins with a single beating heart shared between the thoraxes. Extensive ultrasound examination suggested an extremely poor prognosis, Therapeutic termination was performed at 11 weeks.

Conclusion(s): Given that single embryo transfers are able to shed light on the real incidence of conjoined twins developed on day 2/3 or on day 5/6, this is of interest mechanistically. Thus, it should be taken into account when trying to determine the true incidence of conjoined twins and ultimately trying to understand why these anomalies occur. The importance of early expert vaginal ultrasonography in pregnancies resulting from assisted reproductive technologies is emphasized.