Putting down the pitchforks for a moment, we are in a wave of industry wide layoffs. Some quick Googling says that you qualify for pregnancy disability leave in California at 36 weeks (about 4 weeks before birth). Getting ready to file the paperwork doesn't qualify you or infer any protected status.
No pitchforks (I would agree that isn’t helpful), simply taking steps to ensure assertion of someone’s rights and that a rigorous independent examination of the situation occurs.
This!
Unless you're working in a dinky little mickey-mouse outfit, I will bet good money that HR consulted their lawyers before firing. Which means we have two parties here, and one party has already been advised on a course of action by their lawyers.
It's a shitty thing to do, but my money is on the company being in the clear, legally.
You can bet your ass that the company covered theirs.
* US Department of Labor Complaint (as this touches FMLA): https://www.dol.gov/agencies/whd/contact/complaints
* Do not discuss it further with anyone except your partner and your attorney ("lawyer up").
* Apply for any unemployment benefits immediately.
* Create a paper trail with any existing documents and any further communications with the employer. Do not communicate in any medium you cannot generate a paper trail.
Not an attorney, not legal advice.