NASHVILLE, DEC. 20 -- Researchers at Vanderbilt University gave radioactive pills to pregnant women during the 1940s, university officials have confirmed.

A follow-up study during the 1960s concluded that three children born to women who took the pills likely died because of the tests.

The revelation accompanied other recent announcements by the Department of Energy about previously secret nuclear explosions and tests on human subjects conducted since World War II. DOE is looking for information on the Vanderbilt experiments or other radiation tests performed on civilians during the Cold War, said department spokeswoman Mary Ann Freeman.

On Dec. 8, DOE revealed that researchers gave radioactive pills to 751 pregnant women seeking free care at a prenatal clinic run by Vanderbilt University.

The pills exposed the women and their fetuses to radiation 30 times higher than natural levels, about the same as an X-ray. The doses were not considered unsafe at the time.

In a March 1951 report in the American Journal of Obstetrics and Gynecology, the researchers said they wanted to study iron absorption in pregnant women.

That article does not mention monitoring the long-term effects of radiation on pregnant women or their children. But a Vanderbilt follow-up study in the 1960s shifted its focus to that subject.

A study published in 1969 in the American Journal of Epidemiology concluded that three of the children born to the women likely died because of the radiation exposure: an 11-year-old girl who died of a tumor; an 11-year-old boy who died of cancer; and a 5-year-old boy who died of lymphatic leukemia.

Vanderbilt officials said researchers kept documents of the study until they were destroyed in the 1970s.

"The researchers who were working on that maintained their own files," said Vanderbilt spokesman Wayne Wood. "They were not Vanderbilt property. They belonged to the researchers themselves."

Vanderbilt officials said they don't know if the women were told of the possible effects of radiation or even if they knew they were being given radioactive pills.

Sen. Jim Sasser (D-Tenn.) has asked Energy Secretary Hazel R. O'Leary for an expanded report on the radiation experiments. He called the Vanderbilt study "deeply disturbing" in a statement Saturday.