A U.S. medical advisory group recommended providing women free birth control and other preventive health services under the nation’s healthcare overhaul.

The 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 evidence supporting contraception is quite straightforward. It works,” said Dr. Alfred Berg, a member of IOM‘s Committee on Preventive Services for Women.

The IOM noted that women with unplanned pregnancies were more likely to put off or neglect prenatal care and to smoke, drink or experience depression.

The recommendation to add birth control is a big gain for organizations like the American Congress of Obstetricians and Gynecologists and Planned Parenthood, but is likely to stoke opposition from conservative and religious groups.

“I’m really taken and pleased with the concept of making contraceptive methods available to women in general,” said Dr. James Martin Jr., ACOG‘s president. “It’s just a shame that so many pregnancies in this country are unplanned and unwanted.”

“Covering birth control without co-pays is one of the most important steps we can take to prevent unintended pregnancy and keep women and children healthy,” said Dr. Vanessa Cullins, vice president for medical affairs at Planned Parenthood Federation of America in a statement.

The U.S. Conference of Catholic Bishops has urged the Department of Health and Human Services to exclude birth control as a service, and strongly opposes IOM‘s recommendations.

“Without sufficient legal protection for rights of conscience, such a mandate would force all men, women and children to carry health coverage that violates the deeply-held moral and religious convictions of many,” said Cardinal Daniel DiNardo, chairman of the Committee on Pro-Life Activities of the bishops’ conference.

IOM also recommended free screening for gestational diabetes, testing for human papillomavirus (HPV) in women over 30, counseling for HIV and sexually transmitted infections, lactation counseling, screening for domestic violence and yearly wellness visits.

Health and Human Services has the final say over what services will be offered. Health Secretary Kathleen Sebelius called the IOM report “historic.”

The IOM is an independent, nonprofit organization that works outside of government to provide health-policy advice.

Research suggests the public would be supportive of birth control being added to the list of services.

A Thomson Reuters/NPR survey in May found 76.6 percent of respondents believed private insurance plans, without government assistance, should cover some or all costs associated with birth control pills, such as Yasmin, the popular birth control pill from Bayer.