I had an emergency c-section, where I lost my child. My boss(person A) shared with his/ser spouse(person B) that I had the emergency c-section (baby had not passed yet). The spouse(person B) later that day had a meeting with someone(person C) that use to work at the same company as I did. That person(person C) recognized the last name (not a common name) and asked if they knew so and so. The spouse(person B) said yes, that (person A) is my spouse and then proceeded to tell (person C) that one of (Person A's) employees had an emergency c-section. Percon C asked if it was so and so, but Person B could not remember the name. Person C, knew I was the only one that wroked for Person A that was pregnant. Is this a violation of HIPAA?

No, because HIPAA only applies to the people that have control of your medical records. What your boss did was unethical and if there is someone above him you can complain to, I would.