PITTSBURGH (AP) _ Multiple abdominal organ transplants are still in the early stages of development where failure is common, but hope remains high despite the death of another toddler following the risky surgery, experts say.

''We're in areas that are essentially unchartered,'' said Dr. Marc Rowe, chief of pediatric surgery at Children's Hospital of Pittsburgh. ''What we're doing is making tentative steps and then very carefully analyzing where we've been and what we've learned before we make any decision about the next one, when we'll do one or whether we'll do one.''

The fifth of six children in the country to undergo a multiple abdominal organ transplant died Friday. Three-year-old Rolandrea Dodge of Fruitland, N.M., survived six weeks with a transplanted liver, pancreas, stomach, small intestine and portion of a large intestine, and was awaiting another set of organs.

Four other recipients died shortly after the transplants, and the sole survivor, Calvin Oliveira, 14 months, of Deerfield Beach, Fla., was doing well Friday, despite a seizure earlier in the week and a bout of pneumonia, said Dr. Tony D'Alessandro, a transplant fellow at the University of Wisconsin.

The boy received a small intestine and liver Dec. 31 at the University of Wisconsin Hospital and Clinics in Madison.

''Every organ that's been transplanted has had its early problems,'' D'Alessandro said. ''There are hurdles that you have to go over and along the way you have to learn from everything that's been done in order for things to progress.''

The death of five patients is ''very disappointing,'' said Dr. James W. Williams, director of transplantation at Rush-Presbyterian-St. Luke's Medical Center in Chicago.

''But this is what happened in the early days of liver transplantation,'' he said.

Rolandrea, better known as Rolly, was with her parents, Brandon and Cyndi Dodge, when she died in the hospital's intensive care unit.

The child's chances of withstanding another five-organ transplant, providing a suitable donor could have been found, began to dwindle Friday as her condition swiftly deteriorated. Her name was placed back on the transplant waiting list Wednesday, four days after tests showed her small intestine was being rejected by her body's natural immune system.

Doctors do not know whether any of the other four organs transplanted Nov. 29 were rejected or to what degree, Rowe said.

The child was born with a disorder that prevented her intestines from absorbing food and liquids.

The nation's first multiple abdominal organ transplant was performed in 1983 by Dr. Thomas E. Starzl of the University of Pittsburgh, who pioneered liver transplants. That first patient, a 6-year-old girl, lived only a few hours.

Arthur Caplan, director of the Center for Biomedical Ethics at the University of Minnesota, questioned the ethics of the operation.

''Even if it worked well and people were living with a good quality of life, I'm still not sure there are enough potential donors,'' Caplan said. ''It's very rare to have someone with five good organs.

''I'm also not sure society is going to view giving them all to a single person is the best thing to do. I don't,'' he said. ''I think if you can spread the organs to more people, that is what should be done. The ethical principle should be to save the most lives.''

Intestines are especially difficult to transplant because of the extremely technical nature of the surgery, the lack of biological markers indicating organ rejection, and the bowel's ability, unique among organs, to counterattack the patient's immune system, D'Alessandro said.

The longest survivor of a multiple organ abdominal transplant, Tabatha Foster, 3 1/2 , of Madisonville, Ky., died last May, six months after receiving five organs at Children's Hospital.

''Unfortunately, many, many children are in desperate need of having this sort of operation,'' Rowe said. ''We can't possibly think about the success and failure. What we're thinking about is trying to have a child who has a fatal disease ... and trying to have them live and have a good life.''