A grandfathered health plan is any plan that was in effect on March 23,2010 and remains in effect today without making certain changes generally relating to cost sharing. Grandfathered plans are permitted to make changes to comply with the ACA. Grandfathered plans do not need to comply with some of the ACA requirements, like zero cost preventive coverage.
Any plan, individual, small group, large group, self-funded, employer, religious or otherwise was able to grandfather a plan.
The ACA includes contraception as a mandatory preventive service that plans must cover at zero cost to the subscriber. Recently the Supreme Court upheld an employer's right to exclude some forms of the mandatory contraception methods on the basis of religion.
If you are unsure of your benefits you can request the plan SBC (Summary of Benefits and Costs). The SBC is an ACA mandated form any employer or individual health plan will be able to provide it to you, though it's not required to indicate whether or not the plan is grandfathered.