Yahoo Medical Coverage, does it start day 1 as new employee?

Hi all, Is anyone aware if new employees get medical coverage from day 1? I know some companies have 30/60/90 day waiting periods. I'm wondering because I'm trying to get all of my ducks in a row this weekend, and won't be hearing back from the recruiter until Tuesday the earliest. I may be accepting an offer from Yahoo, but my start date wouldn't be for another month and I'm currently paying into Cobra. #yahoo #newhire #benefits #medicalcoverage