The U.S. Institute of Medicine recommended providing women free birth control and other preventive health services under the country's healthcare overhaul.
The IOM 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."
Other services recommended by IOM include 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.
The U.S. Department of Health and Human Services has the final say over what services will be offered. Department of 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.