PITTSBURGH -- A woman who attacked a romantic rival, killing her fetus, was convicted of third-degree murder under a seldom-used state law.

Corinne Wilcott, 21, of Erie, cried as a jury in Erie County Court returned the verdict against her Wednesday. She also was convicted of aggravated assault, simple assault and terroristic threats in the attack on Sheena Carson, which resulted in the death of Carson's fetus.

Wilcott faces 20 to 40 years in prison on the murder charge when she is sentenced May 6, and could be sentenced to up to 67 years with the addition of the other charges.

The jury returned its verdict after deliberating for more than eight hours on Tuesday and Wednesday. The jury, which at one point asked the judge to repeat instructions regarding third-degree murder, found her innocent of a first-degree murder charge, which would have carried a life term.

"Clearly, the jury spent a lot of time going over the evidence. There was a lot of complex medical evidence to digest," prosecutor Jack Daneri said. "They arrived at the correct judgment."

Wilcott was charged under a seldom-used state law -- one criticized as unconstitutional by Wilcott's attorney, Tim Lucas -- that allows for the death of a fetus caused by an attack to be prosecuted as a homicide.

Attorneys did not know whether this was the first time a person had been convicted under the law.

Lucas said he planned to appeal several issues, including the constitutionality of the fetal homicide law. During an earlier attempt to have the charge thrown out, Lucas argued that the law doesn't make sense because it conflicts with the state's abortion law about what constitutes a human being.

Under the state's abortion law, it is a crime for a woman to terminate her pregnancy after the first 24 weeks, whereas a person could be charged with murder for killing a fetus of any age under the fetal homicide law, Lucas said.

"The judge decided (the law) was constitutional. If it wasn't, then she couldn't be prosecuted," Lucas said.

In ruling the law constitutional before trial, Judge John Trucilla, said that although a pregnant woman can choose to have an abortion, she has no choice in an attack that kills her unborn child.

At trial, prosecutors painted Wilcott as a woman fueled by anger and jealousy, saying she attacked Carson after a graduation party June 8, 2002, because Wilcott's husband, Kareem, had gotten her pregnant.

Carson, 19, said Wilcott dragged her to the ground by her hair and punched and kicked her repeatedly. She told police that during the attack, Wilcott yelled, "I told you I was going to get you for sleeping with Kareem."

Prosecutors said Erie County's forensic pathologist ruled after an autopsy that Carson's fetus, which was 15 to 17 weeks old, died from blunt force trauma to Carson's abdomen.

An expert hired by defense suggested that bacteria detected in Carson's placenta led to the death.