It's definitely suspect. You can file a claim with the U.S. DOL and possibly your state DOL if Missouri has an analogous law to FMLA. It would not be a bad idea to speak with a local employment lawyer.
With most discrimination cases, the employee does not have a "smoking gun", clear evidence that the protected classification (in this case, a person exercising her rights under FMLA and/or a woman (pregnancy)) was a motivating factor for the employer's actions. It would be important for you to act quickly to protect your rights (you mentioned that this happened to another woman not long after it happened to you). Discrimination claims have fairly short time frames to file the administrative complaint with the appropriate agency.
I would be happy to schedule a meeting with you to discuss your potential claims.
Mr. Walter's answers are not intended to create an attorney-client relationship and are based on only the limited information provided in the question. Thus, they should not be considered as legal advice, and persons seeking legal advice should contact Mr. Walter directly and/or another attorney with a law license in the state in which your situation arose. Mr. Walter is licensed to practice law in Missouri and Illinois.
This seems like a clear violation of the FMLA (family medical leave act). Under the statute, a person on leave must be put in the same or equivalent position upon return from leave that they held when they left for leave. Failure to do so is prima facie evidence of a violation.
Missouri has very favorable employment laws and it might be wiser to pursue this claim under the Missouri Human Rights Act for sex discrimination due to pregnancy. You need to contact the Missouri Human Rights Commission immediately to file your charge before the expiration of 180 days from the date the discrimination occurred. Add to the fact that another person in a similar situation was treated the same, and you have a pretty good discrimination claim.
As a side note, I would not recommend filing a charge without the help of an employment attorney. You can ruin your case early on by filing a deficient charge.
Contact an employment attorney as soon as you can.
Hope this helps,
It appears you have a claim for employment discrimination. You were a member of a protected class (woman and pregnant), you suffered an adverse employment action and they do not seem to have a justifiable reason for this. I would contact your local human rights office or the EEOC who will conduct a free investigation and if the facts warrant it sue your employer. You should also contact a reputable employment lawyer.