In 1821, Connecticut became the first state to regulate abortion, outlawing it after quickening and forbidding the use of poisons to induce one post-quickening. This marked the beginning of state-level abortion regulation in the U.S.

In 1829, New York made post-quickening abortions a felony and pre-quickening abortions a misdemeanor. This was followed by 10 of the 26 states creating similar restrictions within the next few decades, in particular by the 1860s and 1870s.

Anthony Comstock created the New York Society for the Suppression of Vice, an institution dedicated to supervising the morality of the public.

The Comstock Law, passed by the United States Congress, made it illegal to deliver through the U.S. mail any "obscene, lewd, or lascivious" material. It also prohibited producing or publishing information pertaining to abortion, birth control, and venereal disease, including to medical students.

By 1900, abortion was normally a felony in every state, with some exceptions for cases where the woman's health was at risk or the pregnancy resulted from rape or incest. Despite the laws, abortions continued to occur and became increasingly available.

Margaret Sanger founded the American Birth Control League, which would later become Planned Parenthood Federation of America in 1942.

The American Birth Control League became Planned Parenthood Federation of America.

The U.S. Supreme Court case Griswold v. Connecticut struck down one of the remaining contraception Comstock laws in Connecticut and Massachusetts. However, Griswold only applied to marital relationships, allowing married couples to buy and use contraceptives without government restriction.

Colorado became the first state to decriminalize abortion in cases of rape, incest, or in which pregnancy would lead to permanent physical disability of the woman.

Hawaii became the first state to legalize abortions on the request of the woman.

New York repealed its 1830 law and allowed abortions up to the 24th week of pregnancy.

Washington held a referendum on legalizing early pregnancy abortions, becoming the first state to legalize abortion through a vote of the people.

The Supreme Court decision Doe v. Bolton clarified that under Roe v. Wade, state governments may not prohibit late terminations of pregnancy when necessary to preserve the life or health of the mother, including physical, emotional, psychological, familial, and age-related factors.

The U.S. Supreme Court in Roe v. Wade invalidated all state laws prohibiting or restricting abortion and set guidelines for the availability of abortion.

The Hyde Amendment, a federal legislative provision, was first attached to annual appropriations bills. It bars the use of federal Medicaid funds to pay for abortions except in cases of rape, incest, and life endangerment.

President Ronald Reagan announced the Mexico City policy, which withholds U.S. federal funding from NGOs that provide abortion services.

In the case of Planned Parenthood v. Casey, the Court abandoned Roe's strict trimester framework but maintained its central holding that women have a right to choose to have an abortion before viability.

The U.S. House of Representatives and U.S. Senate moved to pass measures banning the procedure of intact dilation and extraction, commonly known as partial birth abortion. President Bill Clinton vetoed those bills in April 1996 and October 1997 on the grounds that they did not include health exceptions.

Medical abortion via mifepristone and misoprostol was approved for abortion in the United States by the FDA.

The Born-Alive Infants Protection Act (BAIPA) was enacted by an Act of Congress and signed into law by George W. Bush. It asserts the human rights of infants born after a failed attempt to induce abortion.

The House approved the Partial-Birth Abortion Ban Act to ban intact dilation and extraction, with an exemption in cases of fatal threats to the woman.

The United States Senate passed the Partial-Birth Abortion Ban Act.

President George W. Bush signed the Partial-Birth Abortion Ban Act into law, but a federal judge blocked its enforcement in several states just a few hours after it became public law.

Congress passed and President Bush signed into law the Unborn Victims of Violence Act, also known as Laci and Conner's Law, allowing two charges to be filed against someone who kills a pregnant mother (one for the mother and one for the fetus).

The Supreme Court upheld the nationwide ban on the procedure of partial birth abortion in the case Gonzales v. Carhart, signaling a substantial change in the Court's approach to abortion law.

The Supreme Court ruled in Whole Woman's Health v. Hellerstedt, sweeping away forms of state restrictions on the way abortion clinics can function.

New York passed the Reproductive Health Act (RHA), which repealed a pre-Roe provision that banned third-trimester abortions except in cases where the continuation of the pregnancy endangered a pregnant woman's life.

Alabama House Republicans passed a law that will criminalize most abortion if it goes into effect. Dubbed the "Human Life Protection Act", it offers only two exceptions: serious health risk to the mother or a lethal fetal anomaly.

The U.S. Supreme Court upheld an Indiana state law that requires fetuses which were aborted be buried or cremated.

Alabama governor Kay Ivey signed the bill into law, primarily as a symbolic gesture in hopes of challenging Roe v. Wade in the Supreme Court.

The court declined to review a lower court decision which upheld a Kentucky law requiring doctors to perform ultrasounds and show fetal images to patients before abortions.

The U.S. Supreme Court struck down the Louisiana anti-abortion law.

Texas lawmakers passed the Texas Heartbeat Act, banning abortions as soon as cardiac activity can be detected, typically as early as six weeks into pregnancy.

The U.S. Supreme Court issued a denial of the order late on September 1, 2021, allowing the Texas Heartbeat Act to remain in effect.

Merrick Garland, the Attorney General and head of the United States Department of Justice, sued Texas over the Texas Heartbeat Act.

The FDA approved the distribution of mifepristone via mail.

Colorado passed into law its Reproductive Health Equity Act, which assures abortion rights for all citizens of the state.

Oklahoma imposed a ban on elective abortions after Oklahoma Governor Kevin Stitt signed House Bill 4327. The bill bans elective abortion beginning at conception.

The Supreme Court overruled both Roe and Planned Parenthood v. Casey in the Dobbs case on originalist grounds that a right to abortion cannot be found in the U.S. Constitution.

Texas and Missouri immediately banned abortions with the exception only if the pregnancy was deemed to be particularly life-threatening.

The Minnesota state Senate passed a bill guaranteeing women's rights to abortion and other reproductive medicine which was signed into law on January 31.

Judge Kacsmaryk ruled for the Alliance Defending Freedom, reversing the FDA's approval and banning mifepristone across the United States after seven days.

The state government repealed the 1902 law to allow the 2022 law to take precedence.

In June 2024 abortion in Iowa was made illegal after 6 weeks of gestation, with exceptions for rape, incest, foetal abnormalities, and the mother's life.

The court ruled that the Alliance Defending Freedom lacked standing to bring the suit.

President Donald Trump reinstated the Mexico City policy.

2024 Nevada Question 6 needs to be approved again to enshrine abortion in the state's constitution, while legislators in Hawaii and Virginia proposed similar amendments to codify abortion rights in 2026.