NASHVILLE, Tenn (Reuters) - Two U.S. states drew closer on Wednesday to legislating tougher restrictions on abortion with both Iowa and Tennessee seeking governors’ signatures that would ban the procedure after 20 weeks.

Women in the United States have the right under the Constitution to end a pregnancy, but abortion opponents have pushed for tougher regulations, particularly in conservative states.

A Tennessee bill banning abortions after 20 weeks was sent to the desk of Governor Bill Haslam after it was passed by the state’s Republican-controlled House on Wednesday.

Haslam, a Republican, has not made a decision on whether he will sign the measure into law and will discuss the bill with the state’s attorney general, his spokeswoman Jennifer Donnals said.

Attorney General Herbert Slatery could not be reached for comment.

Iowa Governor Terry Branstad, also a Republican, said he would sign on Friday a 20-week abortion ban. The bill was passed by the Republican-controlled House and Senate last month.

There are 24 states that impose prohibitions on abortions after a certain number of weeks, according to the Guttmacher Institute, which tracks reproductive policy.

Seventeen of these states ban abortion at about 20 weeks.

The Tennessee bill would require women to undergo a test of viability and gestational age before a doctor performed an abortion. Doctors who violate the law could face felony charges. The bill does not make exceptions for rape or incest. It does allow for abortions if the mother’s life or health is at risk.

“We’ve made significant progress as a legislative body in recent years to give a voice to the unborn,” Republican representative Matthew Hill said in a statement.

Iowa’s bill bans abortions once a pregnancy reaches 20 weeks and stipulates a three-day waiting period before a woman can undergo any abortion. It does not make exceptions for instances of rape or incest. It does allow for abortions if the mother’s life or health is at risk.

The American Civil Liberties Union and Planned Parenthood, a group that provides family planning services, including abortions, filed a lawsuit challenging Iowa’s waiting period.

“The governor, lieutenant governor and Iowa legislators have waged an outright war on women’s access to safe and legal abortions,” said Suzanna de Baca, president and chief executive of Planned Parenthood of the Heartland.