BBC News, 16 Jan 03
Roe v Wade: Key US abortion ruling
Abortions were made legal in the United Sates in a landmark 1973 Supreme Court judgement, often referred to as the Roe v Wade case.
By a vote of seven to two, the court justices ruled that governments lacked the power to prohibit abortions.
The court's judgement was based on the decision that a woman's right to terminate her pregnancy came under the freedom of personal choice in family matters as protected by the 14th Amendment of the US Constitution.
The decision - on 22 January 1973 - remains one of the most controversial ever made by the Supreme Court.
The ruling came about when 25-year-old single woman Norma McCorvey, under the pseudonym "Jane Roe", challenged the criminal abortion laws in Texas which forbade abortion as unconstitutional - except in cases where the mother's life was in danger.
Henry Wade was the Texas attorney general who defended the anti-abortion law.
Ms McCorvey first filed the case in 1969. She was pregnant with her third child and claimed that she had been raped. But the case was rejected and she was forced to give birth.
However, in 1973 she filed an appeal with the US Supreme Court and was represented by Sarah Weddington, a Dallas attorney.
Her case was heard on the same day as that of a 20-year-old Georgia woman, Sandra Bensing. They argued that the abortion laws in Texas and Georgia ran counter to the US constitution by infringing women's right to privacy - and won.
The case created the 'trimester" system that:
But over the past decades anti-abortion campaigners have gained ground. More than 30 states have adopted laws limiting abortion rights.
In 1980 the US Supreme Court upheld a law that banned the use of federal funds for abortion except when necessary to save a woman's life.
Then in 1989 it approved more restrictions, including allowing states to prohibit abortions at state clinics or by state employees.
The result of these restrictions is that many women have to travel further to get an abortion, often across state borders, and pay more for them. According to the pro-choice movement, poor women are penalised most by these restrictions.
Although abortion is a constitutional right, 80% of rural areas have no abortion providers and the situation is getting worse.
Norma McCorvey announced in 1987 that her rape testimony in 1969 had been false.
Now a born-again Christian, she converted to the pro-life lobby, and two years later Sandra Bensing followed suit.
But Ms McCorvey's attorney, Sarah Weddington, insists that the rape testimony was not a factor in the Roe verdict, and that her decision to change sides has no bearing on the ruling.
The greatest legislative triumph of the pro-life lobby was the Supreme Court's ruling in Planned Parenthood v Casey in 1992.
While upholding the Roe v Wade ruling, it also established that states can restrict abortions even in the first trimester for non-medical reasons.
The new laws must not place an "undue burden" on women seeking abortion services. However, it is the woman and not the authorities who have to prove that the regulations are damaging.
As a result many states now have restrictions in place such as requirements that young pregnant women involve their parents or a judge in their abortion decision.
Others have introduced waiting periods between the time a woman first visits an abortion clinic and the actual operation.
Some states also provide information that has to be presented to women having abortions which could discourage them from having the operations.