Gov. Mike Parson of Missouri on Friday signed into law a bill outlawing abortions after eight weeks of pregnancy, joining several other states this year in enacting measures designed to limit women’s access to the procedure.

The decision by Mr. Parson, a Republican, was not a surprise. It continued a season of legislative success for conservatives who oppose abortion and who see an opening to ultimately press their case to the Supreme Court.

“I’m honored to lead a state with so many people committed to standing up for those without a voice, and commend the Legislature for getting this bill to my desk,” Mr. Parson said when lawmakers passed the abortion bill. He called it “a strong message to the nation that here in Missouri, we will always stand for life, protect women’s health and advocate for the unborn.”

[Read more about the efforts of anti-abortion activists across the country.]

The Missouri law, which will almost certainly face a legal challenge, bans abortions at eight weeks of pregnancy — a time that is often before a woman knows she is pregnant — and thereafter; the law makes no exceptions for cases of rape or incest. Doctors measure the length of a pregnancy from the first day of a woman’s last menstrual period, rather than from the date of conception, which is usually about two weeks later but can be very hard to know with precision. In general, a woman is considered eight weeks pregnant about six weeks after conception.