Medical/Maternity leave

Medical leave/maternity leave question: So I went to the doctor on the 15th and requested that I be out on medical leave starting the 17th as that would be my Monday start of my work week. I faxed the doctors note over to my job and they have been up in arms since Thursday saying they need more medical information other then I am to start maternity leave. They are saying that the note is not sufficient enough to cover me under a medical leave.I am currently 3 cm dilated and 80% effaced and 37 weeks pregnant although my job is very accommodating it is a lot for me as I have experienced extreme swelling since five months pregnant. My question is...by law do they need to know the medical reason as to why I am out or is that my confidentiality.? Does the note that I provided sufficient enough for a medical/maternity leave? I am not covered under FMLA since I have not been with the company for a year but I have two weeks of sick time and vacation time accrued that I can use before my short-term disability kicks in. Has anyone else experienced something similar to this?