Depends on your company policy. My employer permits short and long term disability pay when medically needed during pregnancy. I don't have to use sick, vacation or personal time before getting disability pay as most companies require.
I'm 32 weeks and have been on bed rest since 28 weeks but negotiated working from home with full regular pay until delivery. Short term disability pay at 60% will begin on delivery date for at least 12 weeks. If medically needed, I can extend it to 26 weeks.
So thankful to work for an employer with a heart.
Your short term should kick in for any medical reason that you are unable to work as long as doctor fills out the needed forms. Just be aware to ask how long your short term disability will last. I know someone who only gets 6 weeks paid-period. Then they can file FMLA, but there is no pay for that.
Your short term disability should cover your maternity leave, not just for bed rest.