HAUPPAUGE, N.Y. (AP) _ A 16-year-old girl charged with arranging her father's murder after he forced her into incest has suffered a miscarriage, and laboratory workers are trying to determine whether he could have been the father of the fetus, officials said Wednesday.

Cheryl Pierson's pregnancy had not been revealed previously. The 16-year- old cheerleader was charged last month with hiring a classmate to shoot her father, James Pierson, 42, as he left his home for work on Feb. 5.

''She was pregnant and there was a question of whether her father was the father of her child,'' said Charles Hirsch, Suffolk County medical examiner.

On Tuesday, Miss Pierson ''began spontaneously to have a miscarriage'' and was taken to a Port Jefferson hospital, he said.

Samples were taken from Miss Pierson's blood and the placenta. They were sent to a private laboratory which compared them with blood taken from her father's body during an autopsy, Hirsch said.

''There's no guarantee that we will be able to test it successfully,'' he said. Officials said they didn't know when the results would be completed.

Paul Gianelli, Miss Pierson's attorney, did not return a telephone call placed to his office for comment on Wednesday.

The identity of the father of the child is at issue because social service agencies said Miss Pierson never reported the alleged incest, said to have continued over a four-year period, before her arrest.

Miss Pierson and Sean Pica, 17, of Coram, have pleaded innocent to murder charges. Miss Pierson is free on $25,000 bail while Pica remains in the Suffolk County Jail in Riverhead on $100,000 bail.

Police say Miss Pierson paid $400 to Pica one day after the murder.

Miss Pierson said in a recent interview that she was too frightened to report abuses. ''I discussed it with him, and he always threatened me and said that I had no proof,'' she said. ''He'd say that I'd never get away with it. He threatened to kill me. I knew he wouldn't kill me, but I was so afraid of him, and it was scary because of his temper.''

Gianelli said the murder occurred after Miss Pierson saw her father frolicking with her younger sister and feared he would start an incestuous relationship with her.