COLUMBUS (AP) — An Ohio woman accused of suffocating her three young sons over a 13-month period has unsuccessfully appealed a court order that she undergo a psychiatric evaluation.

At issue is whether a confession made by defendant Brittany Pilkington can be used at her trial.

The Bellefontaine woman faces three counts of aggravated murder in the deaths of a toddler and two infants in 2014 and 2015. She has pleaded not guilty.

Pilkington’s attorneys argue the confession should be tossed after their experts concluded Pilkington has brain damage and a low IQ. Logan County Judge Mark O’Connor has ordered an independent psychiatric evaluation.

An appeals court upheld O’Connor’s order in May, and the Ohio Supreme Court on Wednesday declined to hear the case. Pilkington’s attorney called the decision disappointing.