If you poke a fetus of a certain gestational age, it might recoil. Its body might release stress hormones. Its neural pathways might sputter.

But is it in pain?

Antiabortion advocates say yes. For years, they’ve used the pain claim to justify bans on abortions beyond 20 weeks after conception. Twelve states have such “pain-capable unborn protection” laws, according to the National Right to Life Committee. West Virginia became the latest state to join after the legislature overrode a governor’s veto in March, the first such veto in decades.

Yesterday, a more unusual fetal-pain bill passed the Montana house. HB 479 would not outlaw abortions, but after 20 weeks, it would require doctors to give fetuses painkillers before aborting them, or performing any kind of “invasive” medical procedure.

The bill now carries significant exemptions. After a fiery debate in committee this month, HB 479 was amended to allow mothers to forgo fetal anesthesia if they gave informed consent. (There would still be paperwork, a talk, and some kind of government-issued pamphlet about fetal pain.)

Still, all of the Montana House’s Democrats have opposed the bill. “The intent is very clear,” said Rep. Jenny Eck (D) during floor discussion Tuesday. “It’s to insert politicians and their political wills into the exam room.”

The author of HB 479, freshman Rep. Albert Olszewski (R), is personally against abortions. But he says that this is not an antiabortion bill.

“The main intent is looking at a health-care policy issue that is now pertinent,” he said. Olszewski, a practicing orthopedic surgeon, explained that fetal surgery is becoming more and more common in Montana. He believes the law needs to catch up.

Anesthesia for fetuses is complicated

It is true that surgeons can now fix all kinds of birth defects and life-threatening conditions from inside the womb. In some cases, they do not even have to slice the womb open; they can insert endoscopic equipment that is thinner than the lead in a mechanical pencil.

In all these situations, though, anesthesia is already part of standard medical procedure.

“In terms of fetal surgery that’s just what we do,” said Elaina Lin, an assistant professor of medicine at the University of Pennsylvania, who sounded a little puzzled when asked how Montana’s law might change the behavior of surgeons.

Lin practices anesthesiology at Children’s Hospital in Philadelphia, and has written a survey of fetal anesthesia techniques with her colleague Kha Tran. She emphasized that fetal pain research is highly controversial. “By the late second or early third trimester, what most clinicians can agree on is that the pathways are there for them to feel some sort of stimulation,” she said.

Whether those signals are interpreted as pain — whether they are truly and consciously felt — is a question that can only be answered with a better understanding of the fetal brain, and better understanding of consciousness.

Fetuses are routinely sedated during surgery, for reasons beyond the fear that the operation might cause them pain. Anesthetics stop a fetus from kicking around, making the operation safer. And though a fetus might not be conscious of pain, its body can respond to pain and stress in ways that interfere with its recovery. Painkillers alleviate that problem.

That can happen directly or indirectly. During fetal surgery, women typically receive general anesthesia or sedation, making them unconscious or semi-conscious and pain-free. These drugs pass through the placenta to affect the fetus. For more involved operations, doctors inject extra painkillers directly into the fetus.

Olszewski agrees that his law probably won’t affect how most fetal surgeons work. His bill does not specifically require a separate course of anesthesia for the fetus, only that fetuses receive “adequate relief from physical pain and suffering” — an intentionally vague term allowing for medical discretion.

It’s less clear how Olszewski‘s law would affect late-term abortions.

In the second trimester, 13 to 27 weeks after the woman’s last period, the most common abortion technique involves widening the cervix and using tools to take the fetus out through the birth canal. This is called “dilation and evacuation,” and the mother receives anesthetics. To avoid what some might call a “partial-birth” abortion, many providers use chemicals to stop the fetus’s heart in the womb before taking it out, though that is not a medically necessary step.

For as long as the fetus is alive during the abortion, it will experience some anesthetic effects depending on what drugs the mother receives. But would indirect anesthesia suffice to provide the “adequate relief” from pain that HB 479 demands?

Just to make sure, Olszewski would prefer that fetuses are anesthetized directly during an abortion. He says that doctors can readily learn how to use an ultrasound-guided needle to deliver a cheap dose of painkillers to the fetus. “If a doctor is providing abortion, they could do the anesthetic themselves,” he said. “It’s not an amazing skill.” (Any time a needle enters the womb there are the risks of accidental punctures, internal bleeding and infection.)

Is this about abortions or not?

Above all, Olszewski hopes that his law raises awareness about fetal pain. He’s seen the research on this subject and interprets it in a different way. “Starting at 18 to 20 weeks, you can say with empirical certitude that there are physiological responses to pain,” he said. Whether that counts as pain pain, he says, more of a philosophical question.

Whether HB 479 is a fetal pain bill or an abortion bill is also something of a philosophical question.

The Supreme Court has ruled that states may outlaw abortions for fetuses old enough to live outside the womb. Most gynecologists say the cutoff is around 24 weeks after the woman’s last period.

But antiabortion advocates say that fetuses can feel pain as early as 20 weeks after conception (by rule of thumb that’s about 22 weeks since the mother’s last period). This claim, though medically unsupported, forms a moral foundation for laws that roll back the abortion window to 20 weeks.

(It should be noted that late-term abortions are quite rare in the United States. The Guttmacher Institute estimates that 1.2 percent of abortions are performed on women more than 20 weeks pregnant.)

Simply spreading the notion of fetal pain is a technique to discourage women from obtaining late-term abortions. In 2006, the U.S. House Republicans pushed a symbolic bill that would require doctors to tell women “there is substantial evidence” that their fetuses can feel pain 20 weeks after fertilization. Doctors would also have to offer anesthesia for the fetus.

Though that measure didn’t become law, 12 states have passed fetal pain notification laws requiring women to be told about fetal pain. With its new opt-out provision, Olszewski’s bill now more closely resembles one of those laws. Women may decline the fetal anesthesia as long they have listened to the notification about it.

Olszewski said that he also did not want to propose an outright ban on late-term abortions because he doubted that it would get past Democratic Governor Steve Bullock. The governor has been reluctant to allow restrictions on a woman’s access to abortion.

On Tuesday during the floor discussion, several Montana house Democrats criticized Olszewski’s bill as an antiabortion machination.

“I’m sorry if women’s bodies get in the way of some people’s political beliefs,” said Eck. “I’m sorry that women have autonomy, self-determination and constitutional rights. But that’s the way it is. And until men can carry babies or artificial incubators can build babies, you’re stuck with that reality: that women have our own rights, our own lives, our own wills.”