According to the SCOTUS decision, most laws restricting abortion in America violated a constitutional right to privacy under the Due Process clause of the 14th Amendment to the U.S. Constitution.
The ruling basically overturned all state and federal laws restricting abortions. It centrally held that a mother could abort her pregnancy for any reason up until the point at which the baby, referred to in the ruling by its scientific developmental stage name 'fetus', became 'viable'. It defined viability as the baby having the potential to live outside the mother's womb, albeit with artificial aid, and placed this term at between 24-28 weeks.
The court also held that abortion after viability must also be available in order to protect a woman's health, and this 'health' was defined broadly in a companion case called 'Doe vs. Bolton'.
The court based its ruling on its desire to protect personal freedoms and privacy. A woman should be able to make medical decisions involving her health along with her doctor, and the government should in no way be interfering in this process.
Of course never anywhere in their ruling did the court recognize the very apparent fact that there is not just one life, not just one person's health, being affected by a decision to abort. There is a baby alive inside of the mother.
