One of the five surviving septuplets born 12 weeks prematurely to a California English teacher died this morning, and another is "very, very sick," hospital officials said.

James Martin Frustaci, who weighed 1 pound, 8 ounces when he was born 16 days ago, "expired at 11:04 a.m. from complications of severe hyaline membrane disease," a spokesman for Childrens Hospital of Orange County said. He said the cause of death would be listed as heart and lung failure.

Another infant, Bonnie Marie, who weighed 1 pound, 12 ounces at birth, was also worsening because of the same condition, caused by the tendency of immature lung sacs to collapse.

The three other infants -- Patricia Ann, Stephen Earl and Richard Charles -- are all under 2 pounds and need ventilators to breathe but appear to be improving, hospital officials said.

The babies' mother, Patricia Frustaci, had been taking the fertility drug Pergonal before conception and was confined to a hospital bed during the last two months of her pregnancy. One of the seven babies was stillborn, and another died of the same lung disease less than three days after the May 21 Caesarean delivery.

Although at least six sets of sextuplets are alive in the world, no more than five babies born to one woman at the same time have survived more than a few days in the United States.

Some doctors have said careful monitoring during the administration of fertility drugs such as Pergonal should be able to prevent the conception of so many babies, but the Los Angeles clinic that initially treated Frustaci has disputed that claim. National statistics show that 5 percent of Pergonal patients will have pregnancies resulting in three or more babies. Frustaci has a 14-month-old son born after she took Pergonal.

Frustaci, 30, and her husband, Sam, 32, were with their tiny son at the hospital's newborn intensive care unit when he died today, the father told reporters.

Dr. Carrie Worcester, director of the unit, said, "He went into complete respiratory arrest in his parents' arms."

In an article in this week's People magazine, Patricia Frustaci said she rejected a chance to abort all or some of fetuses when she learned in January that she was carrying septuplets. The couple are members of the Church of Jesus Christ of Latter-day Saints, and Patricia Frustaci said that "with our religious background and all we had gone through to have kids, that just wasn't an option."

During the pregnancy, her weight swelled from 115 to 187 pounds. She had to eat several meals and take oxygen to try to supply as many nutrients as possible to the fetuses. She could not lie on her back because her swollen uterus might press down on blood vessels and cause her to faint or cut off oxygen to the fetuses.

"The babies were taking so much out of my body. Just drawing and drawing," she said. "Nobody can have that much reserve for that many."

Her obstetrician, Dr. Martin Feldman, decided to perform a Caesarean section when the babies were 12 weeks premature because he feared Frustaci's rising blood pressure would cause several to be stillborn. He said the baby born dead probably had been denied necessary nutrients because the high blood pressure had resulted in a poorly developed placenta and umbilical cord.

Doctors have expressed confidence that the three healthiest babies will survive but will need to stay in the hospital until at least mid-August, when they would have been born if the pregnancy had gone full term.

The two infants who died earlier, Christina Elizabeth and David Anthony, were buried privately May 31.