Updated

A third premature infant has died after accidentally being given an adult-sized dose of a blood thinner medication at a hospital last week.

The baby girl named Thursday Dawn Jeffers died late Tuesday, six days after being born at Methodist Hospital.

"They killed my baby. Why, oh why?" the child's mother, Heather Jeffers, her eyes red from crying, asked her mother as they hugged Wednesday morning outside the younger woman's apartment.

Two other girls, D'myia Sabrina Nelson and Emmery Miller, both less than a week old, died Saturday at Methodist's Neonatal Intensive Care Unit.

They and three other babies were given too-strong doses of heparin, which is often used to prevent blood clots that could clog intravenous tubes, after a pharmacy technician accidentally stored adult doses in the neonatal unit's drug cabinet.

Thursday Dawn's grandmother, Joanna Pruitt, condemned the care the child received.

"Don't just walk away and say, 'Oh, OK, I trust you.' There's too many people to trust people, and that's what we did. We trusted nurses and doctors to take care of this baby," Pruitt said during an emotional, impromptu news conference outside the apartment in a low-income neighborhood on the city's east side.

"And there was nothing wrong with her. She was healthy — only premature, seven weeks early, that was it," Pruitt said.

Thursday Dawn died at Riley Hospital for Children, a sister institution to Methodist, where she was transferred after the heparin overdose.

The three surviving babies still were in critical condition Wednesday because they are premature but were not considered in danger from the overdoses, Methodist spokesman Jon Mills said.

"We are all saddened by this news and our hearts are with this family, and all the families who have been affected," the hospital said in a news release.

Sam Odle, president and CEO of Methodist Hospital, said Tuesday that the hospital will offer to provide restitution to and pay for counseling for all six families affected. Methodist and Riley are part of Clarian Health Partners.

"We are acutely aware that nothing can adequately compensate these families for their loss," Odle said.

Since the overdoses, the hospital has taken steps to ensure the mistake does not happen again. It will no longer keep certain doses of heparin in inventory, and all newborn and pediatric critical care units will require a minimum of two nurses to validate any dose of heparin, Odle said.

It is not the first time the hospital has administered an overdose of the drug, Odle said. A similar overdose of heparin was given to two patients in the hospital's Pediatric Intensive Care Unit in 2001. Both recovered, he said.

Staff members involved with Saturday's mistake were receiving counseling and taking time off until they felt comfortable returning to work, hospital officials said.

Deb Hutchens, a neonatal nurse practitioner, said nurses were devastated. "We all feel very deep sorrow. It's just going to be a very long healing process for all of us," she said.