While working as a nurse in the New York slums, Margaret Sanger witnessed the plight of poor women suffering from frequent pregnancies and self-induced abortions. Believing that these women had the right to control their reproductive health, Sanger published this pamphlet that simply explained how to prevent pregnancy. Distribution through the mails was blocked by enforcement of the Comstock Law, which banned mailing of materials judged to be obscene. However, several hundred thousand copies were distributed through the first family-planning and birth control clinic Sanger established in Brooklyn in 1916 and by networks of active women at rallies and political meetings.