Pregnancy is a pre-existing condition? yes and no
According to the HIPAA regulations of 1996, pregnancy can NEVER (no matter what state or what insurance company) be considered a pre-existing condition in group health plans.
For reference: http://cms.hhs.gov/hipaa/online/group/family/Pregnancy_content.asp?record=480021
The honest answer is sometimes. It all depends on whether or not the organization offering insurance has opted for HIPAA regulated insurance.
So ask several insurence comapnies to find out?
COBRA is expensive. I think it about $500 - $700/month.