This is from the White House Office of the Press Secretary:
“Covering contraception saves money for insurance companies by keeping women healthy and preventing spending on other health services. For example, there was no increase in premiums when contraception was added to the Federal Employees Health Benefit System and required of non-religious employers in Hawaii. One study found that covering contraception lowered premiums by 10 percent or more.”
This goes to answering a question on costs I had on my previous post.