From my experience with STD and FMLA:
1. I was only granted short term disability for 6 weeks after delivery by Cigna. Apparently being a paramedic and pregnant doesn't qualify as a disability. Even though my job was dangerous to my unborn child I had 2 choices work, or don't get paid.
2. You do not have to pay back STD if you wind up quitting your job, you are receiving benefit from the premiums already paid prior to the claim.
3. FMLA is only 12 weeks, not 6 months as someone else posted. Your company (or theirs) may offer extended leave of absence, but FMLA is only 12 weeks.
4. Definately talk to your human resources dept. They are going to give you the best answers because not ever company carries the same coverage even if the insurace company is the same. They can tell you what type of leave you are able to take and how long they can/will hold your position.
I went through He77 with my pregnancies because of my job. I was forced to make choices between the well being of my unborn babies and making ends meet for the ones I still had to feed. It sucked monkey. I never want to go through the process again. Ever.