Margaret Higgins Sanger advocated for birth control in the United States and Europe during the late nineteenth and early twentieth centuries. Although people used contraceptives prior to the twentieth century, in the US the 1873 Comstock Act made the distribution of information relating to the use of contraceptives illegal, and similar state-level Comstock laws also classified discussion and dissemination of contraceptives as illegal. Sanger helped to repeal the Comstock Act and similar laws so that women could legally use contraceptives to control their fertility and the sizes of their families. In 1916, Sanger opened the first birth control clinic in the US in New York City, New York. Later in life, Sanger formed several advocacy organizations that promoted access to contraception, including the Planned Parenthood Federation of America. Sanger's advocacy increased women's access to contraception and helped change the United States' social and legal perceptions of birth control.

In 1914, Margaret Sanger published “Family Limitations,” a pamphlet describing six different types of contraceptive methods. At the time Sanger published the pamphlet, the federal Comstock Act of 1873 had made distributing contraceptive and abortion information through the US postal service illegal. The Comstock Act classified contraceptive information as obscene and limited the amount of information available to individuals about preventing pregnancies. In 1915, Sanger’s husband was charged with violating the Comstock Act for distributing “Family Limitations” and was sent to jail for 30 days. The case sparked many birth control activists to lobby for the repeal of the Comstock Act. By inciting controversy during a time when the Comstock Act limited contraception access, Sanger’s pamphlet “Family Limitations” increased women’s knowledge about various methods of preventing pregnancy.

Mary Coffin Ware Dennett advocated for social reform in the United States in the early twentieth century, particularly regarding sex education and women's rights to access contraception. Dennett authored several publications on sex education and birth control laws. She also worked to repeal the Comstock Act, a federal law that made it illegal to distribute obscene materials through the US Postal Services. During the early 1900s, Dennett distributed a pamphlet she wrote on sex education called, The Sex Side of Life, through the post, which triggered a series of legal challenges that contributed to the dismantling of the Comstock Act. Dennett was an advocate for sex education and contraceptives, and her actions helped increase women's access to information about reproductive health.