Wisconsin is pushing to expand a controversial program that uses federal Medicaid funds to provide free birth-control pills, vasectomies and other forms of contraception to low-income people, an effort made possible by the federal health-care overhaul.

It and 26 other states already provide free contraception and other reproductive-health services through a Medicaid pilot project to lower-earning women who otherwise wouldn't qualify. Among other things, the women get access to prescription birth control, Pap smears, testing for sexually transmitted diseases and, in some states, infertility treatments. Women qualify for Wisconsin's program if they make up to $21,600 a year for single people—twice the federal poverty level.

Wisconsin's plan has already been in political cross-hairs at times. The state touts it as cost-effective. Jason Helgerson, the state's Medicaid director, credits it with preventing unplanned pregnancies that "regardless of your political stripes, I don't think anybody wants." But critics point out that it allows girls and boys as young as 15 to participate without having to notify their parents.

Now, Wisconsin wants to widen the reach of its plan. Where funding previously was conditional and states had to reapply regularly, a provision in the health-care law allows states to make their plans permanent and get federal funding faster. Wisconsin applied in June to raise the qualifying limit to $32,490—a move that would expand the program's reach.

"That's just insane," said Julaine Appling, president of Wisconsin Family Action, a conservative lobbying group. "That is a whole new segment of our population that is now seeking reproductive health care on taxpayer money." Her group and others say they will try to thwart Wisconsin's expansion, though they see little chance, because Democrats control the legislature and the governor's office.

Wisconsin says about 53,000 people receive extra family-planning help under Medicaid. With federal Medicaid funds reimbursing 90% of the cost of most family-planning services, the state spent $18.4 million on the program in 2008.

That same year, the state's health department estimates, the program prevented an estimated 11,064 unplanned pregnancies, at a savings it estimates at $139.1 million—savings, it says, in expenditures to cover the birth of those children and other health care for them.

Most state Medicaid programs have a higher income limit for pregnant women, while setting a lower limit for women after they give birth and often excluding childless adults. Proponents of Wisconsin's approach say states can save money by providing more family-planning aid earlier instead of waiting until a woman gets pregnant to widen the net for Medicaid.

The U.S. Conference of Catholic Bishops, which put pressure on lawmakers over the health-care overhaul's treatment of restrictions on abortion coverage, says it opposes the provision in the law that makes it easier to make the state plans permanent and will alert its bishops at the state level.

To provide coverage for family planning and nothing else, said Richard Doerflinger, an associate director of the group, reflects "a very dismissive view of women: The reproductive system is the only part of you we're interested in, and our interest is only to make sure it doesn't produce."

Most states in the program—including Wisconsin—also provide coverage for the "morning-after pill," which is opposed by antiabortion groups. Like Medicaid generally, the program doesn't cover elective abortions.

Wisconsin's program covers NuvaRing birth control. Andy Manis for The Wall Street Journal

Ariel Wilberg, a 20-year-old student in Edgerton, Wis., says she enrolled in the program two years ago to cover the cost of her birth-control pills. With a part-time bookstore job that pays $10 an hour, she couldn't afford to pay for the NuvaRing prescription birth control she now takes. She estimates it would cost her about $300 for the three-month supply she gets at a Planned Parenthood outlet.

"It's very nice to know that I'm healthy in terms of I don't have to worry about pregnancy," she said.

Write to Janet Adamy at janet.adamy@wsj.com