MEXICO CITY – More details have emerged about one of the oldest sets of human remains found in the Americas, a young woman nicknamed “Naia” whose nearly complete skeleton was discovered in 2007 in a water-filled cave in Mexico’s Yucatan Peninsula.

A study has determined that as thought, the young woman was between 15 and 16 when she died by falling into the cave about 13,000 years ago. There are signs she may have recently given birth.

Mexico’s National Institute of Anthropology and History said Wednesday the study was based on X-ray and other tests on the skeleton, which has been pulled out of the cave bit by bit over the last several years.

The study was conducted by James Chatters of Applied Paleoscience, a consulting firm in Bothell, Washington, and other researchers.