Help!!! Have an E5 that lied to an NCO. This was the first offense but this isn't the first lie.?

I just took over a platoon as a new E6 and I have a pregnant Soldier that was supposed to be reporting to pregnancy pt. I recently found out that she has not been going and has told the NCOIC of that pt program that she would be with her unit and was not true. This goes back at least a month. Can anyone help me with some recommendations with my plan of action.