Multi-day hearings are taking place in Knoxville to determine whether Tennessee's planned execution of Christa Pike on September 30 would violate her Eighth Amendment rights protecting against cruel and unusual punishment, in what would be the first execution of a woman in the state in over 200 years.

Pike was convicted in 1996 of the 1995 murder of 19-year-old Colleen Slemmer, a fellow Job Corps colleague, when Pike was 18 years old. The Tennessee Supreme Court appointed a special master to investigate the case, citing the unique logistical challenges posed by Pike's gender, her extensive history of sexual trauma, and several medical conditions that could complicate the delivery of lethal drugs.

At the centre of the legal argument is Pike's blood disorder, thrombocytosis, which her legal team say creates what they describe as a dual and paradoxical risk during the lethal injection process. On one hand her condition could cause clotting at the IV site, preventing drugs from being delivered. On the other it could cause catastrophic bleeding. Either scenario, her lawyers argue, could result in significant and unnecessary suffering.

Tennessee has used a single drug, pentobarbital, in executions since last year. Pike's legal team described the compound as notoriously corrosive, comparing its potential effects on surrounding tissue to drain cleaner if the catheter were to fail. All lethal injections also carry a risk of pulmonary edema, a condition in which the lungs fill with fluid, which Pike's team argue is an even greater risk given her circulatory system.

Her legal team also raised concerns about the physician involved in a failed execution attempt in May, when IV difficulties caused the procedure to be abandoned. They argued the same doctor is likely to be involved in Pike's execution and pointed to that case as evidence of systemic issues with the state's protocol. The state rejected this argument, saying the two cases are not comparable and that its trained personnel are fully prepared to carry out the procedure.

The hearings also heard from a warden at Riverbend Maximum Security Institution in Nashville, where executions take place, who confirmed that only lethal injection and electrocution are approved under Tennessee law, ruling out any other approaches the defence may have proposed.

A decision from the special master is expected ahead of the September 30 date.