Anti-abortion activists and politicians sometimes like to spread the damaging lie that hormonal birth control works by causing a miscarriage.
The most recent high-profile individual to grab attention for making that claim is Katy Talento, who was announced as a health care policy aide to President-elect Donald Trump on Thursday and who has a history of claiming that “chemical birth control” (whatever that means) causes “deliberate miscarriage” (again, meaning unclear).
In a 2015 article in The Federalist ― rather ridiculously headlined “Miscarriage Of Justice: Is Big Pharma Breaking Your Uterus?” ― Talento, who has a master’s in epidemiology from Harvard but is not a medical doctor, argued:
Progestin in birth control thins the endometrial lining (uterine wall), but a fertilized egg needs a thick, fluffy, blood-rich uterine wall to attach to and begin growth. Without it, the embryo can’t survive, and a miscarriage occurs.
Advocates from both the anti-abortion and pro-abortion-rights camps have disputed that mechanism, Talento admitted in her essay ― but then she went on to argue that long-term birth control use runs the risk of “breaking your uterus for good.”
Here’s why that ― all of it ― is simply not true:
How birth control works
There are many types of hormonal contraception for women, including but not limited to the birth control pill (including combination and progestin-only), the birth control shot and the hormonal IUD (there is also the non-hormonal copper option).
In general, there are a few mechanisms by which those methods help prevent pregnancy. Birth control pills, patches and rings, for example, help the body prevent ovulation by keeping the body from releasing an egg.
“What the hormones will do is prevent an egg from coming out,” Dr. Krishna Upadhya, a pediatrician who specializes in adolescent reproductive health told The Huffington Post. Upadhya is a member of the Oral Contraceptives Over The Counter working group.
“Additionally we can try and prevent the sperm from getting to the egg,” she said. “The hormones can change the mucus in the cervix [to prevent the sperm] from getting to an egg that might have been released.”
Each method has its own specific mechanisms (for another example, the copper IUD prevents the sperm from reaching the egg because sperm “don’t like” copper). But with hormonal birth control, a woman doesn’t necessarily know if during any given month a potential pregnancy was stopped because her body didn’t release an egg or because the birth control method she is taking resulted in changes to her cervical mucus that prevented sperm from reaching the egg, Upadhya said.
Why it’s not a miscarriage or abortion
When people argue that birth control causes miscarriage ― or even that it represents a form of abortion ― they are generally operating under the assumption that any time a sperm and egg have come together, that is considered a pregnancy.
“Some people, whether for religious reasons or other reasons, feel very strongly that there should be no outside interference in eggs and sperm potentially coming together ... that is considered a conception, and anything that interferes with that conception going to term, essentially, is a miscarriage,” Upadhya said. “From a medical standpoint, that is not a definition we use.”
According to the American College of Obstetricians and Gynecologists, pregnancy begins only when a fertilized egg has implanted in the lining of a woman’s uterus, which takes several days. (Plan B ― i.e., the morning-after pill ― is not considered an “abortion” either, because it works by preventing ovulation.)
Oh, and numerous studies have shown that taking birth control early on in a pregnancy does not harm that pregnancy ― nor does taking birth control affect future fertility.
“Birth control is critical to women’s health,” Upadhya said. “It’s really important that we have people who direct our health policy who understand that.”
CORRECTION: This story was updated to more accurately reflect how hormones in birth control can prevent the sperm from reaching the egg.