Eau Claire County Judge Paul Lenz also sentenced Larry Johnson Jr. on Friday to 20 years of extended supervision upon his release for the first-degree sexual assault of a child younger than 13. He received credit for the 287 days already served.
Johnson is accused of having sexual contact with the girl since she was 11, according to the Leader-Telegram. She's now 16.
Police were called Aug. 28 to a hospital on a report of a then-15-year-old girl showing childbirth complications. Police discovered the teen had given birth and the baby girl died of asphyxiation.
A juvenile delinquency petition was filed against the teen.
"The effect on the victim in this case will be forever," Lenz told Johnson on Friday, adding that he hoped the teen will get counseling. "This is not going to be something that will ever go away."
At the end of his confinement, Johnson could be subject to an involuntary civil commitment if he is found to be a sexually violent person under the state's sexual predator law, Lenz told him.
Johnson also was convicted in 1990 two counts of first-degree sexual assault of a child.