n 2001, Sandee Pingatore was determined to find out why her son, Troy, 29, had died in a California hospital while being treated for a drug overdose just hours after she had been told he was stable. But Pingatore was unable to get the hospital to produce a key medical record showing his blood pressure in his final hours.

When the record finally surfaced last year — too late under state law for Pingatore to file a civil lawsuit — it indicated Troy had been in mortal danger for several hours while awaiting care.

In 2006, another California woman, Beth Stover, ran into difficulties when she tried to get medical records to help her understand why her full-term baby had died in her womb.

When she got the records, she noticed something was missing: a strip-paper readout from a fetal monitoring device from Stover's last routine checkup. She eventually got a readout showing normal activity for a mother and her baby, but in a lawsuit she says she doubts it came from her records.

The hospitals involved — Fairchild Medical Center in Yreka, Calif., and Kaiser Foundation Hospital in Walnut Creek, Calif., respectively — deny any wrongdoing.