(CNN) In light of last month's Supreme Court decision that overturned Roe v. Wade and revoked the constitutional right to abortion, much of the Biden administration's response has been focused on protecting access to medication abortion.
Mifepristone -- a pill used to medically induce abortion in combination with another drug, misoprostol -- is approved for use by the US Food and Drug Administration, and some have argued that its federal approval could take precedence over state laws attempting to ban it.
Medication abortion has steadily grown in acceptance since it became an option about 20 years ago and is now used in more than half of abortions, outpacing the aspiration, or surgical, procedure for the first time in 2020, according to data from the Guttmacher Institute, a research group that supports abortion rights.
But medication abortion is not always an appropriate option -- sometimes for medical reasons but more often in the context of the individual situation -- and experts say it's critical to protect access to abortion as broadly as possible.
"Medication abortion is the primary focus of all my research, but I'm the first one to say that it's not a panacea and cannot be the answer for everyone," said Ushma Upadhyay, an associate professor at the University of California, San Francisco's Bixby Center for Global Reproductive Health.
GenBioPro, the manufacturer of generic mifepristone, lists a few reasons for people to avoid using the abortion pill on their website. They include allergies to the drug, long-term use of steroids for things like autoimmune disorders, and history of a bleeding disorder. It's also not a viable option for the few people who do get pregnant while an IUD is in place.
Overall, experts say that these clinical exceptions are uncommon.
"It is very rare that medication abortion would be absolutely contraindicated for someone," said Dr. Jen Villavicencio, lead for equity transformation at the American College of Obstetricians and Gynecologists.
Dr. Alice Mark, an abortion provider in Massachusetts and interim medical adviser to the National Abortion Federation, estimates that she has a patient with these considerations only one or two times each year.
More restrictive, perhaps, are timing limitations for the drug.
The FDA has specifically approved mifepristone for use in the first 10 weeks of pregnancy, and the vast majority of abortions happen within this timeframe. Nearly 80% of abortions in the United States in 2019 were performed at nine weeks or earlier, according to the US Centers for Disease Control and Prevention.
But there are two main reasons why a person may seek an abortion after the first 10 weeks of pregnancy, Upadhyay said: There is new information learned or barriers to care that prevent earlier action.
"Many people do have delayed recognition of pregnancy, particularly younger people, adolescents, people who've never been pregnant before," she said.
Otherwise, there might be new knowledge about their health or the health of the fetus, changes to their economic situation or partner relationship, or other new information.
Even when patients have their minds made up, barriers to access can add delays to the timeline.
"We've had participants in our research tell us that by the time they've collected the funding needed to make the trip and to pay for the abortion, they will call the clinic and learn that the price has gone up [with the increased gestational age]. And then they have to spend more time gathering the funds," Upadhyay said.
These barriers are generally the same that exist across health care more broadly for more disadvantaged populations.
Although it might be easier to find an abortion provider than a general physician -- at least before the Supreme Court ruling changed the provider landscape -- most don't have the economic resources to fund a "time-sensitive health emergency," said Kirsten Moore, director of the Expanding Medication Abortion Access Project.
"There's a real burden on the patient to put all this together," she said. "I don't think it's finding the abortion provider, per se, that's the challenge. It's coming up with the resources to actually bring it all together."
Clinical considerations aside, experts say that individual preferences and the nuances of each situation mean medication abortion is not right for everyone.
"Most people who get to my clinic kind of know what the choices are when they get there. And I think a lot of people who are trying to decide about abortion do their own research," Mark said.
There's a medical screening for every patient, just like with any other procedure, but "the main consideration is really just like, 'What do you feel like is going to fit best for you in your life?' " she said.
Generally, medication abortion allows the person to manage the process at home or at their own pace. This option can provide more privacy but typically comes with more pain, cramping and bleeding for a longer time. The aspiration procedure, on the other hand, is a quicker process that includes pain management and confirmation from a medical professional that it is complete. It can be a better option for people for whom pregnancy is already a traumatic experience, experts say.
If you are a low-income mom of two already and you are pregnant and don't want to be, you might like the idea of a noninvasive option that you can manage at home. But you might also be dealing with more than anybody does on a regular basis, so you might just want to get into a clinic and get things over with," Moore said.
In any case, both medication abortion and the aspiration procedure have been proved to be safe and effective.
"Individual patients may have their own needs and preferences, and it's important that my patients be able to choose the method that is right for them, " Villavicencio said.
"In the future of abortion care in a post-Roe landscape, there will be new benefits to each intervention -- medication abortion, for example, because of its proven safety via mail order and the (surgical) abortion procedure because patients who have to travel to a different state will know with certainty that they are no longer pregnant immediately upon completion of the procedure."