As someone pointed out earlier, schools don't fall under HIPAA. Doctors, health insurance companies, hospitals, etc all fall under that law, but the only thing a private entity deals with that would fall under that is your insurance information. There may be other claims, though it appears that she tried to assert those other claims already and lost.
I guarantee you that’s not true. Any entity that has collected any personally-identifiable, confidential health information is bound to hold it in confidence. You know those insurance forms that you filled out and gave to your employer that are now sitting in a file somewhere? They cannot distribute it, nor use any of it against you.
The ultimate user of the information is the insurance company, but everyone in the trail is held to the same standard.
It is against the law for any employer to discriminate against a pregnant person - it’s against the law to ask an applicant, and it’s against the law to take action against an employee when it comes to pregnancy.