I have good news for Catholic employers worried about providing health insurance to their employees which might be used to keep sex from leading to babies. The time-honored doctrine of double effect is all the conscience protection you really need!
Double effect is a way of reasoning about complex situations which involve both moral positives and moral negatives. Let's run through the checklist:
1. The intended act must be good in itself. The intended act may not be morally evil.
Providing health insurance for employees is surely a good thing in itself. Ayn Rand would have disagreed, but that's usually a strong indication that you're doing the right thing.
2. The good effect of the act must be that which is directly intended by the one who carries out the act. The bad effect that results from the act may be foreseen by the agent but must be unintended.
Catholic employers aren't providing health insurance for the purpose of making sure their employees have access to condoms, etc. Merely foreseeing that the insurance might be used that way is acceptable.
3. The good effect must not be brought about by using morally evil means.
You wouldn't be buying abortion insurance with fine print about general health issues.
4. The good effect must be of equal or greater proportion to any evil effect which would result.
So long as doctors save lives more often than they take them by abortion, check this one off the list.
5. Acts that have morally negative effects are permissible only when truly necessary, i.e., when there are no other means by which the good may be obtained.
The 'mandate' part takes care of this. You didn't choose to include reproductive choice services, so you're off the hook.
(But I understand if you keep this reasoning under your hat until it's clear that "my religious conscience is being violated!" has failed as a political tactic.)