Case Study is:

A 34-year-old white woman with no other children became pregnant. At four months of gestation ultrasound revealed conjoined twins. The treating physician on the Maltese island of Gozo recommended transfer to St Mary's Hospital, Manchester where he had trained. Because of a long standing agreement between Malta and Great Britain the patient was transferred to the care of the British National Health Service.

On transfer magnetic resonance imaging revealed significant problems with the pregnancy. The smaller of twins was not expected to survive. The parents, because of their religious belief that “everyone has a right to life”, declined the option to terminate the pregnancy. The pregnancy was allowed to continue for 42 weeks before delivery by caesarean section on 8 August 2000. The combined birth weight of the infants was 6000 g. Both infants were immediately intubated. They were ischiopagus tetrapus conjoined twins linked at the pelvis with fused spines and spinal cords, and with four legs.

Jodie, the healthier of the two had an anatomically normal brain, heart, lungs, and liver. She shared a common bladder and a common aorta with Mary. Mary was severely abnormal in three aspects: brain, heart, and lungs. She had a very poor “primitive” brain. Her heart was vastly enlarged, very dilated, and poorly functioning. There was a virtual absence of functional lung tissue. Mary was not capable of independent survival. She lived on borrowed time, all of which was borrowed from Jodie.

There were three options:

(1) Permanent union until the certain death of both twins probably within 3–6 months or at best in a few years.

(2) Elective separation. In the hospital's view this would lead to Mary's death but give Jodie the opportunity of a “separate good quality life”. There was a 5%–6% chance of death at separation. Jodie would subsequently require several operations for bladder and genital repairs. She had musculoskeletal abnormalities which would require future surgical intervention. Separation would allow Jodie “to participate in normal life activities appropriate to her age and development”.

(3) Urgent (emergency) separation. Prognosis would be markedly reduced in the event of Mary's death or cardiac arrest of Jodie with mortality projected at 60% for Jodie, 100% for Mary.