Are you thinking of Lydria Fairchild? In her case she wasn’t sent to prison. However, her two children were taken from her and placed in foster care for a while. Lawyers were refusing to represent her, due to the belief that DNA evidence is too strong to fight. On the plus side, she was pregnant again. So a court officer was present during her third child’s birth.

Despite being at the birth and witnessing blood draws from both mother and child, the court still claimed she was being untruthful somehow. Thankfully, that birth and its evidence was peculiar enough to attract a lawyer to finally represent her. Only after that did the investigation into potential chimerism arise.

More info here - …asu.edu/…/case-lydia-fairchild-and-her-chimerism…