Iowa’s highest court has upheld a law saying the state can enforce a ban on most abortions after about six weeks of pregnancy.

The law bans abortions after early signs of cardiac activity can be detected in a foetus or embryo – but makes exceptions for cases of rape, incest, foetal abnormalities and when the mother’s life is in danger.

The decision made on Friday reverses a temporary block of the law, which was initially passed by the state legislature in July 2023.

The Iowa Supreme Court rejected the lawsuit by Planned Parenthood, in a 4-3 ruling which held that the law does not violate citizens’ fundamental rights under the state constitution.

The decision, published on the court’s website, held that laws restricting abortion were only unconstitutional if the state cannot show a “rational basis” for the law.

Justice Matthew McDermott wrote in the majority opinion that the law was “rationally related to the state’s legitimate interest in protecting unborn life”.

Chief Justice Susan Christensen wrote in her dissenting view that the majority “strips Iowa women of their bodily autonomy” and relies heavily on “the male-dominated history and traditions of the 1800s”, while ignoring the progress made in women’s rights since then.

Iowa Governor Kim Reynolds – who initially signed the 2023 law – welcomed the decision in a statement.

“There is no right more sacred than life, and nothing more worthy of our strongest defense than the innocent unborn,” she said, praising the court for upholding “the will of the people of Iowa”.

According to the Iowa Capital Dispatch, the state previously banned abortions after 20 weeks of pregnancy.

Iowa is the latest state to tighten its abortion laws since the US Supreme Court overturned the 1973 Roe v Wade decision, which rescinded the nationwide guarantee to an abortion.

Since then, a patchwork of abortion laws has emerged as more conservative states restrict access to the procedure.

The Guttmacher Institute reports that as of June, 14 US states have a total ban on abortion – including Alabama, Kentucky, Louisiana and Texas.