Superior Court Judge Charles Lamm sentenced Carruth after hearing emotional testimony from the parents of Cherica Adams, who was eight months pregnant when she was shot four times in November 1999. She died a month later.
Her mother, Saundra, said she forgives Carruth, but "in no way do I think he should get off easy for what he has done."
"He's already gotten the greatest of mercy - his life is spared," she said, her voice breaking. "Let him take the punishment not of a little boy, but of a man one time. Let him know he needs some help."
Saundra Adams also said her daughter's child, born by emergency Caesarean section, has cerebral palsy.
Adams, 24, was mortally wounded in an attack prosecutors said Carruth set up to avoid paying child support. Prosecutors said he used his white Ford Expedition to block Adams' car so a hired gunman could shoot her.
Carruth was convicted of conspiracy to commit murder, shooting into an occupied vehicle and using an instrument with the intent to destroy an unborn child.
He is to serve at least 18 years, 11 months, and as much as 24 years, four months. He will get credit for the roughly 14 months he was jailed awaiting trial.
Carruth stared at the judge, showing no emotion, as Lamm announced the sentence. Defense lawyer David Rudolf immediately filed notice of appeal.
"My son is innocent," Carruth's mother, Theodry Carruth, said outside court. "My son did not try to destroy his own unborn baby."
Lamm rejected a defense motion to vacate Carruth's convictions, which Rudolf said were inconsistent with the jury's decision Friday to acquit Carruth of first-degree murder. The verdict implied that some jurors gave up their reasonable doubt about the prosecution's case in order to reach a compromise verdict, Rudolph argued.
"In our view, a compromise verdict violates the defendant's state and federal due process rights," he said. "If they have a reasonable doubt, they should not give that up simply to reach a verdict."
CBSNews.com Legal Analyst Andrew Cohen says it will be difficult for Carruth's attorneys to overturn the jury verdict.
"Even though it appears to have been a compromise that may not make sense legally," Cohen says, "judges, especially appellate judges, hate to second-guess juries."
Adams' parents and other relatives embraced one another as the hearing ended.
Adams' father, Jeffrey Moonie, said he was pleased with the outcome, but still had a question for Carruth.
"I would like to hear why. I would like to know why," he said. "I'm still surprised he has not shown any reaction so far."
Adams' and Carruth'son, Chancellor, also suffered physically as a result of the shooting, Saundra Adams testified.
Cherica Adams lost a substantial amount of blood in the attack, and her son - delivered prematurely after the shooting - is developmentally disabled and has cerebral palsy.
"He can't hold onto his bottle ... he has trouble even holding onto the rattle," Saundra Adams testified. "He's not anywhere near taking his first step. The doctors are telling me he might not take a first step until he is three years old or older."
Prosecutor Gentry Caudill argued that Carruth played a lead role in the crime and took advantage of Adams' "misplaced" trust in him. He also noted that Carruth has shown "not one ounce of remorse," for Adams' death.
"He offered no assistance as Cherica lay dying from those wounds," Caudill said.
Rudolf asked the judge to consider mitigating circumstances, including the fact that Carruth had no criminal record prior to the shooting, and that he served as a mentor to youngsters.
"I think it was pretty clear it was a compromise verdict," Rudolf said after the hearing. "By definition, the jurors were compromising their reasonable doubts. If we have to try this case a second or third time, that's the way we'll go."
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