Washington (AFP) - The southern US state of Alabama is set to enact a law that would mean jail for doctors performing abortions, even in cases of rape and incest -- part of a push by conservatives countrywide to curb family planning services.

Those backing the move say they hope it is challenged all the way to the Supreme Court, forcing a review of the landmark 1973 Roe v. Wade ruling that unduly restrictive state regulation of abortion is unconstitutional.

The measure, approved by the Alabama House of Representatives, sets prison terms of between 10 and 99 years for doctors who perform abortions.

The only exception would be instances where the mother at serious risk or where the child would not survive outside the womb because of some lethal condition.

The measure needs approval by the state's Republican-controlled senate before it can be signed into law by Republican Governor Kay Ivy.

Deeply conservative and religious Alabama would then file an appeal to any successful legal challenge in the US Supreme Court, hoping the case sets a new precedent overturning legal abortion nationwide.

"This bill is simply about Roe v. Wade," said its author, Republican representative Terri Collins, during debates on the chamber floor.

"The decision that was made back in 1973 would not be the same decision that was decided upon today if you re-looked at the issue," Collins said.

Conservatives are counting on support at the Supreme Court, where liberal justices are in a minority after the arrival of two conservative members appointed by President Donald Trump.

While the Alabama measure is seen as particularly draconian, at least 28 US states have introduced more than 300 measures since the start of the year limiting abortion rights, according to activists.

Kentucky and Mississippi are two states that have banned abortions as soon as a fetus's heartbeat is detectable, or around the sixth week of pregnancy. Similar measures are being adopted in Georgia, Ohio, Missouri and Tennessee.

A judge has blocked the implementation of the Kentucky law, while the Mississippi law is set to come into effect in July.