Conjoined twins after intracytoplasmic sperm injection and transfer of day-3 embryos

Objective To report a case of conjoined twins conceived through assisted reproduction after intracytoplasmic sperm injection (ICSI) and the transfer of three eight-cell embryos on day 3. Design Case report. Setting Assisted reproduction unit of a private hospital. Patient(s) A 32-year-old patient underwent ICSI and received three embryos. Intervention(s) Ovarian stimulation and ICSI. Main Outcome Measure(s) Images of the embryos and ultrasound images of the fetuses. Result(s) One embryo measuring 7 weeks, relatively big in size and bizarre in appearance with one heartbeat, was detected on transvaginal ultrasound at 6 weeks, 4 days of pregnancy. Two weeks later, another ultrasound was performed; two fetuses with a common heart were observed. In 10th week of pregnancy, two fetuses with two hearts and an attached thorax were observed. A diagnosis of thoracopagus was made, and the pregnancy was terminated. Conclusion(s) Conjoined twins conceived through assisted reproduction are extremely rare. This case, which occurred after transfer of cleavage-stage embryos, suggests that ovulation induction, ICSI, and assisted hatching may also play roles in addition to other factors commonly proposed to be responsible for conjoined twining, such as in vitro culture condition, culture time, and blastocyst-stage transfer.