Missouri first US state to ban abortion after top court ruling

The US Supreme Court's overturning of America's constitutional right to abortion gives all 50 states the freedom to ban the procedure, with nearly half expected to do so in some form.

The Midwestern conservative state of Missouri on Friday became the first US state to ban abortion, hours after a Supreme Court ruling struck down decades of constitutional protection of the procedure.

Abortion-rights activists react after hearing the Supreme Court decision on abortion outside the Supreme Court in Washington. (AP)

"Missouri has just become the first in the country to effectively end abortion," state attorney general Eric Schmitt said on Twitter. "This is a monumental day for the sanctity of life."