The Church still has the moral authority to teach morals and right from wrong, and bringing up what you did really cuts your credibility is discussing this topic with reason and logic rather than emotions and feelings.
So if the teacher was embezzling from the school, but happened to be pregnant would that too be horrible when they fired her. Or maybe something more innocuous, maybe she was showing up late and leaving early semi regularly (that too would be breaking her contract, or spending class time on facebook instead of teaching, and she just happened to be pregnant. Is it still horrible and lacking justice? Just because you don’t like the clauses in the contract doesn’t mean the clauses are wrong.
There is a saying in law. “Hard cases make bad law.” This is one of those cases, this one pulls at your heartstrings because she is pregnant and we are pro-life, etc. But making a ruling that the school can’t fire her, or shouldn’t have fired her based on her individual case would create bad law. Both on the civil side (the law suit) and on schools/Church side.