1821   Connecticut passes the first law in the United States barring
            abortions after "quickening."
            

1873   Congress passes "Comstock Laws," prohibiting sending information and devices for the prevention of conception through the mails, on the grounds that such are "obscene, lewd, lascivious, filthy, indecent and disgusting."

1916   Margaret Sanger opens first birth control clinic in the U.S. and goes to jail.

1918   New York Court of Appeals empowers legally practicing physicians to prescribe contraceptives for married couples if necessary "to cure or prevent disease."

1923   Sanger opens Birth Control Clinical Research Bureau, a clinic dispensing contraceptives under the supervision of a physician.

1929   Sanger’s clinic is raided, physicians and nurses are arrested, and supplies and records are seized.

1936   Sanger challenges the "Comstock Laws" by importing a package of diaphragms.   In U.S. v. One Package, the U.S. Circuit Court of Appeals rules that the U.S. Tariff Act of 1930 cannot be construed to forbid the importing of contraceptives for use by physicians in saving lives or promoting well-being.

1937   North Carolina becomes the first state to recognize birth control as a public health measure to provide contraceptive services to low income mothers through its public health programs.

1940   Connecticut upholds a state statute that makes use of contraceptives illegal.

1942   The Birth Control Federation of America, Inc., changes its name to Planned Parenthood Federation of America, Inc.

1960   Food and Drug Administration approves the use of oral contraceptives.

1965   U.S. Supreme Court finds unconstitutional the Connecticut law prohibiting birth control for married couples in Griswold v. Connecticut.

1970   Congress enacts Title X of the Public Health Service Act, providing family planning services, education and research.

           New York enacts the most liberal abortion law in the nation.

1971   Congress repeals most of the provisions of the federal "Comstock Laws."

1972   In Eisenstadt v. Baird, the U.S. Supreme Court strikes down a Massachusetts statute that bars distribution of contraceptives to unmarried people.

1973   Abortion is legalized nationwide by the U.S. Supreme Court’s decision in Roe v. Wade.

1976   Congress adopts the first Hyde Amendment barring the use of federal Medicaid funds to provide abortions to poor women.   This action marks the beginning of a continuing series of amendments to federal laws in order to restrict abortion access to various groups of people receiving medical care through the government.

1977   The Hyde Amendment is revised to allow states to deny Medicaid funding except in cases of rape, incest, or "severe and long-lasting"” damage to the woman’s physical health.

           First reported arson at an abortion clinic, in St. Paul, Minnesota, and first known bombing of an abortion clinic, in Cincinnati, Ohio.

1991   In Rust v. Sullivan, the U.S. Supreme Court rules that family planning clinics which receive Title X funding can be forbidden to answer clients’ questions about abortion.

1992   Planned Parenthood of Southeastern Pennsylvania reaffirms the "core" holdings of Roe v. Wade that women have a right to abortion before fetal viability, but allows states to restrict abortion access so long as these restrictions do not impose an "undue burden" on women seeking abortions.

1993   Newly inaugurated President Bill Clinton revokes the 1988 Title X "gag rule" and restores the previous policy requiring non-directive options counseling and appropriate referrals.

            Dr. David Gunn is murdered outside of Pensacola Women’s Medical Services in Florida.

1994   Dr. John Britton, Lt. Col. Jim Barrett, Shannon Lowney, and Leanne Nichols are murdered in shootings at three abortion clinics.

            In Madsen v. Women’s Health Center the U.S. Supreme Court upholds a Florida Supreme Court injunction establishing a "buffer zone" around an abortion clinic to protect access to its entrance.

1998  On January 29 a bomb at New Women’s Clinic in Birmingham, Alabama, kills an off-duty police officer working as a security guard and critically injures a clinic nurse.

            On October 23 a sniper shoots through a kitchen window and kills Dr. Barnett Slepian in his home in upstate New York.

Sources: 

Planned Parenthood Federation of America
National Abortion Federation