If you opened up the Leavenworth Times, a Kansas newspaper, in the 1850s, you’d see an ad for Sir James Clarke’s Female Pills. These pills, the advertiser bragged, were ideal for bringing on women’s periods—and were “particularly suited to married ladies.”

Then there was Madame Costello, a “female physician” who took out an ad in the New York Herald in the 1840s. She advertised to women “who wish to be treated for obstruction of the monthly period.”

Both ads ran in plain sight, among advertisements for real estate and hair tonics. Both advertised abortions. And for a reader of the time, neither would have raised an eyebrow. Pregnancy was dangerous, and the consequences faced by unwed mothers were severe.

Though the 19th century is seen as a time of more restrictive sexual mores, abortion was actually common: according to at least one estimate, one in every five women at the time had had an abortion. Abortifacients were hawked in store fronts and even door to door. Vendors openly advertised their willingness to end women’s pregnancies. And in private, women shared information about how to prevent conception and induce miscarriages.

Then things changed—thanks in part to doctors determined to make abortions their realm. During the second half of the 19th century, American physicians intent on overseeing women’s reproductive health campaigned to criminalize abortion, sending a common practice underground.

One of the reasons abortion was accepted at the time had to do with how Americans back then thought about the human body. Folk and medical wisdom held that the body was a place of equilibrium. If something occurred to throw the body out of balance—like the cessation of a woman’s menstrual period due to pregnancy—it was seen as a problem that needed to be remedied. Doctors encouraged women to act swiftly if their periods were delayed, and women commonly took so-called “emmenagogues,” drugs designed to stimulate menstrual flow, or used herbal remedies and folk practices like laying in bed with hot bricks to bring on their periods.

If this didn’t work, a woman could buy patent medicines like Sir James Clarke’s Female Pills, which contained oil of savin. Or she could visit a “female doctor” to get an abortion. In the mid 19th century, there were few female physicians, but some women billed themselves as doctors anyway and specialized in women’s health, contraception and abortion.

One such woman was Ann Lohman, who terminated countless pregnancies as “Madame Restell” during her 40-year-long career. Though Lohman had no formal medical training, she made a career selling patent medicines and helping pregnant women who wished to give birth without losing their reputations. Lohman’s business was so well known—and so successful—that it inspired copycats and helped create a booming abortion business in American cities.

This infuriated those who felt that abortion was immoral—and created troubling competition for physicians. At the time, medicine was becoming an actual profession instead of the realm of homegrown practitioners, and the rise of medical schools and accreditation created a class of professional doctors. These physicians were suspicious of the midwives and self-styled “doctors” many women relied on for abortions, and as soon as the American Medical Association formed in 1847, its members began to agitate to make abortion illegal.

To do so, they challenged common perceptions that a fetus was not a person until the pregnant mother felt it “quicken,” or move, inside their womb. In a time before sonograms, this was often the only way to definitively prove that a pregnancy was underway. Quickening was both a medical and legal concept, and abortions were considered immoral or illegal only after quickening. Churches discouraged the practice, but made a distinction between a woman who terminated her pregnancy pre- or post-quickening.

The association’s efforts were led by Horatio Storer, an obstetrician often called the father of American gynecology. Storer didn’t want the medical profession to be associated with abortion, and considered women’s desire to terminate their pregnancies to be tantamount to insanity. He felt that a woman’s biological role was to be a wife and mother, and that to disrupt that path was not just to commit a social crime, but murder.

“We are the physical guardians of women,” read the group’s 1859 report on what it called “criminal abortion.” “The case is here of life or death—and it depends, almost wholly, upon ourselves.”

The group made a concerted effort to delegitimize the work of the women who previously held the majority of knowledge about childbirth and pregnancy, and to prevent women from becoming obstetricians. At the same time, some members of the public grew alarmed by falling birth rates—and, thanks to lobbying by the AMA, connected the issue with the prevalent practice of abortion.

It worked. In 1873, the Comstock Laws banned the publication and dissemination of information about birth control, and anti-abortion laws quickly followed. By the end of the 19th century, every state except Kentucky had abortion laws on the books. (Kentucky followed in 1910.)

These laws didn’t jibe with the practices of many Americans: In the words of historian Leslie J. Reagan, “generations of women desired and needed abortions, and neither law nor church nor taboo could stop them.”

Ending a pregnancy was often a social necessity. Though premarital sex was common, women who gave birth without marrying first were still seen as fornicators, fallen women and even criminals. If a woman became pregnant without a man to marry her, she risked being cast out of her family and society. Since women were discouraged from working and were unable to own property, being thrown out without the support of one’s family often led to disaster.

Americans did not stop getting abortions—they simply went underground. By the early 20th century, patent medicine companies disguised abortifacients as remedies for “female complaints” to evade strict advertising laws, and doctors could no longer legally perform abortions. Only in 1973 did the U.S. Supreme Court rule in Roe v. Wade that laws criminalizing abortion were unconstitutional. By then, generations of women had clamored for abortions—but those who received them did so in secret.