A mother accused of killing six of her babies has appeared in a US court, but prosecutors have told the judge they need more time to file formal charges, the Salt Lake Tribune reported.
Utah police said Megan Huntsman, 39, has admitted to killing six babies immediately after giving birth between 1996 and 2006.
Their tiny bodies were found in boxes in her garage, after her estranged husband alerted police. Remains of seven infants were found, but Huntsman claimed one had been stillborn.
"There is a lot of evidence that is being gathered as we speak," Utah County Attorney Jeff Buhman told the judge on Monday.
"The medical examiner has completed initial autopsies, but we don't expect the reports for a while."
Judge Claudia Laycock gave prosecutors one more week to prepare.
Huntsman is being held in jail in lieu of a $US6 million ($A6.42 million) bail.
