Huntsman, 40, pleaded guilty as charged in February to six counts of first-degree felony murder in her children's deaths. As part of a plea deal, prosecutors had agreed to recommend that the five-years-to-life prison sentences run concurrent to one another.
But at Monday's sentencing hearing, 4th District Judge Darold McDade said concurrent sentencing was "not appropriate" for the crimes. He instead ordered her to serve three of the counts consecutively, while the rest will run concurrently.
"I really thought I'd seen it all until this case came along," the judge told Huntsman before sentencing. "I hoped I would not get the case. What a tragedy."
Utah County Attorney Jeff Buhman said it is unlikely Huntsman will receive an initial hearing in front of the parole board until she has served at least 30 years behind bars. But he believes the woman will spend the rest of her life in prison.
"These were very cold and calculated killings," Buhman said in court. "She was a woman who was remarkably unbelievable and incredibly indifferent. She smothered or strangled six of her own flesh and blood."
In her statement, Huntsman said it was combination of her addiction to methamphetamine and alcohol, an abusive marriage and her own depression that played a part in the killings, which occurred from Jan. 1, 1996, to Dec. 31, 2006.
"Megan is not a monster," sister Jamie Huntsman told the judge Monday. "She's not evil. From what I understand, she was scared."
Letters from two of Megan Huntsman's three daughters were also read aloud in court by her sister.
"No matter what anyone thinks you are, you are a good person," the letter from one daughter reads.
Her youngest daughter wrote that she was "shocked and heartbroken" by her mother's crimes.
"This is not the Mom I know," the letter reads. "The Mom I know was the one who had dinner for us every night, a clean house and was a loving mother. Nobody could guess my mom would do anything like this."
While Megan Huntsman's sister, mother and children made statements in support of the defendant, no one was called by prosecutors to give a statement on behalf of the infants. The woman's estranged husband, Darren West — who fathered the dead infants — was in court during the sentencing hearing, but did not speak to the judge.
In an unusual move, prosecutors called a Pleasant Grove police detective to the stand Monday to detail the case.
Detective Dan Beckstrom said police went to Huntsman's home April 12, 2014. West had called 911 after he found "what he believed was a dead baby in a bag in his garage."