Legal Question in Family Law in Texas

No. Contempt of court is related to disobeying a court's written order. If she knew the statement was false, the court could refer her to the DA for prosecution of perjury. I would not expect that to happen just because it wouldn't take much for her to say that at the time she made that statement to the court, she believed it to be factually accurate.

This actually happens more than you would think. The courts are used to discrepancies about parentage and the district attorney would probably consider your request to prosecute to be more about revenge than anything else.