An Osceola, Wis., woman working as a certified medical technician at the Stillwater prison has been charged with criminal sexual conduct after having liaisons with an inmate and becoming pregnant.

Yvonn N. Lerro-Miller, 37, faces two felony counts of criminal sexual conduct by a correctional employee, according to a complaint filed in Washington County District Court. She has been terminated from her job.

Lerro-Miller told investigators she timed the trysts in a medical exam room with the unidentified 32-year-old inmate to optimize her chances of getting pregnant, according to the complaint. On other occasions, the inmate passed her containers of his semen, which she injected into herself.

Investigators began monitoring the inmate's phone calls to her. A search of his cell uncovered a photo of Lerro-Miller, along with an ultrasound photo.

After police learned Lerro-Miller had a miscarriage in December, DNA tests showed the inmate was the father.