Pennsylvania could be the next battleground in the fight over whether a woman seeking an abortion must have an ultrasound exam and, if so, whether it involves inserting a probe into her vagina.

In Virginia last week, a preabortion ultrasound law derailed at the eleventh hour after opponents portrayed it as "state-sponsored rape" and late-night comedians piled on. (The Daily Show's Jon Stewart joked that it would turn women into "human Popsicles.")

On Tuesday, the Virginia legislature narrowly adopted a revised version that requires only the familiar "jelly-on-the-belly" external ultrasound - a change requested, with chagrin, by a prominent abortion foe, Gov. Bob McDonnell.

"No person should be directed to undergo an invasive procedure by the state, without their consent, as a precondition to another medical procedure," McDonnell said.

Alabama legislators are facing a similar uproar this week over an ultrasound measure there.

The furor has not daunted Pennsylvania Rep. Kathy Rapp (R., Warren), lead sponsor of House Bill 1077, which mandates a preabortion ultrasound test. The bill was passed out of the health committee by a 15-7 vote and is scheduled for House floor action March 12.

Ultrasound legislation aimed at discouraging abortion has been proliferating since the 1990s, and 31 states now have varying laws, according to Guttmacher Institute, a reproductive-health research center. Most statutes do not specify the type of imaging technology, but increasingly they spell out how much detail the exams must provide.

Through seven weeks of pregnancy, when about half of abortions occur, detailed images usually require a "transvaginal" probe because it gets closer to the structures being imaged than an abdominal probe, experts say.

Rapp said she believed her bill, called the Women's Right to Know Act, would require "the ultrasounds on the belly. Any doctor who wanted to proceed to transvaginal ultrasound would have to have a good reason."

But the language of the bill suggests otherwise. While it doesn't mention vaginal ultrasound, it requires the physician to measure the "gestational sac" if an embryo is too small to be seen.

"The gestational sac is often the first thing that most transvaginal ultrasounds can detect at about five weeks," says the American Pregnancy Association, a nonprofit educational organization.

Former prosecutor Patrick Murphy, who is running for Pennsylvania attorney general as a Democrat, on Tuesday called the bill "an outrageous assault on women's rights."

Since Friday, six of the 103 cosponsors of Rapp's bill have withdrawn. House Majority Leader Mike Turzai (R., Allegheny) remains a cosponsor.

Rep. Thomas Killion (R., Chester) said he backed off after doctors told him the bill would subject many women to ultrasounds with a vaginal probe.

"I'm personally pro-life, and I support anything that would discourage abortion," Killion said. "But I reached out to some physicians in the county after hearing their concerns. I think the way this bill is written is problematic. We need to hold some hearings on the bill. It's nowhere near ready for prime time."

Both the Pennsylvania Medical Association and the Pennsylvania section of the American College of Obstetricians and Gynecologists have opposed the bill, saying it would interfere with the doctor-patient relationship and mandate an unnecessary test.

That doesn't mean ultrasounds are unusual in abortion care. Abortion providers readily acknowledge that the procedures are routine - but not to make women change their minds.

Providers do ultrasounds to confirm that a pregnancy is within the clinic's limit - usually 14 weeks or 20 weeks of pregnancy - and to choose the most appropriate abortion method.

Abdominal ultrasound is usually adequate for those purposes, even early in pregnancy, said Dayle Steinberg, president of Planned Parenthood of Southeastern Pennsylvania.

"The majority of procedures in Pennsylvania are first trimester," she said, "and most are picked up through transabdominal ultrasound."

Nationally, about 53 percent of abortions are done at or before seven weeks of pregnancy, and an additional 15 percent are done at eight weeks - well before the first trimester, which goes through 12 weeks, according to federal data.

Antiabortion ultrasound statutes, including Rapp's proposal in Harrisburg, typically require the doctor to offer the patient a chance to hear the heartbeat, watch the ultrasound monitor, and receive information about gestational development - although the patient may refuse in writing. Rapp's bill also requires that the patient be given a sealed envelope with a personal copy of the ultrasound.

Proponents frame such requirements as a matter of informed consent.

"It's about respecting women by trusting her with all the facts to make a truly informed decision regarding the human life she is carrying," Rapp says on her website.

On the contrary, opponents say, it's about guilt-tripping and is condescending to women.

"This bill operates under the guise that women aren't smart enough to understand their own bodies," says the advocacy organization Keystone Progress in an online petition titled "Stop PA's Ultrasound Bill."

It is unclear what the bill's chances are beyond the House, since the Senate does not have a version.