The U.S. health department Monday issued a plan to provide women with free preventive health services, including birth control, under the nation's healthcare overhaul, but gave religious institutions the flexibility to opt out.

The guidelines, which the Health and Human Services Department called ``historic,'' adopted recommendations from a research advisory group released last month.

It added an amendment allowing religious institutions to choose whether to cover contraception services in their insurance.

The U.S. Institute of Medicine report, commissioned by the Obama administration, recommended that all U.S.-approved birth control methods -- including the ``morning-after pill,'' taken shortly after intercourse to forestall pregnancy -- be added to the federal government's list of preventive health services.

The recommendation faced strong opposition from conservative and religious groups that balked at the use of taxpayer money to cover birth control, especially the controversial ``morning-after pill.''

The adoption of the recommendations is a win for organizations including the American Congress of Obstetricians and Gynecologists and Planned Parenthood.

HHS Secretary Kathleen Sebelius and Assistant Secretary Howard Koh will hold a press conference on the guidelines later Monday.