The data is in a report being released Tuesday by the Guttmacher Institute, a reproductive-health think tank whose research is generally respected even by experts and activists who don't share its advocacy of abortion rights.
Report co-author Rachel Benson Gold called the family planning program "smart government at its best," asserting that every dollar spent on it saves taxpayers $4 in costs associated with unintended births to mothers eligible for Medicaid-funded natal care.
Despite such arguments, federal funding for family planning is a divisive issue.
Last month, under withering Republican criticism, Democrats in Congress abandoned an attempt to include an expansion of family planning services for the poor in the economic stimulus bill. One anti-abortion activist, Troy Newman of Operation Rescue, called the short-lived proposal a "shameful population control program that targeted low-income families."
However, Democrats in Congress are not abandoning their overall goal. They plan to push soon for a major funding increase for Title X, the main federal family planning program, as part of broader legislation endorsed by President Barack Obama to reduce the number of unintended pregnancies.
The Guttmacher report provides ammunition for those who will advocate the funding increase.
Surveying data from the 2006 fiscal year, the report says the national family planning program prevented 1.94 million unintended pregnancies, including almost 400,000 teen pregnancies. Based on statistical analysis and projections, these pregnancies would have resulted in 860,000 unintended births, 810,000 abortions and 270,000 miscarriages, according to the report.
Without publicly funded family planning, it said, the U.S. abortion rate would be nearly two-thirds higher, and nearly twice as high among poor women.