You may want to check on your search engine for health insurance for pregnant women. There is no individual or group insurance that will take you now, but I have seen some banners and pop ups for this type of insurance. I don't know what type it is or what it costs, but it can't hurt to check them out.
Answer
Most group insurance companies do not consider pregnancy a pre-exsisting condition. If you are unable to sign up with your employers health insurance you could either wait until open enrollment, or you could apply for medicaid.
Answer: If a GROUP PLAN has maternity coverage, you will be covered.
"Federal law bars group health insurance plans that cover maternity from considering pregnancy a pre-existing condition. This means that if you change group health plans while you're pregnant, your new group health insurer (as long as it covers maternity) can't deny claims related to your pregnancy." http://www.insure.com/articles/healthinsurance/pregnancy.html