WASHINGTON — Democratic presidential candidate Barack Obama says "mental distress" should not qualify as a justification for late-term abortions, a key distinction not embraced by many supporters of abortion rights.

In an interview this week with Relevant, a Christian magazine, Obama said prohibitions on late-term abortions must contain "a strict, well-defined exception for the health of the mother."

Obama then added: "Now, I don't think that 'mental distress' qualifies as the health of the mother. I think it has to be a serious physical issue that arises in pregnancy, where there are real, significant problems to the mother carrying that child to term."

Last year, after the Supreme Court upheld a federal ban on late-term abortions, Obama said he "strongly disagreed" with the ruling because it "dramatically departs form previous precedents safeguarding the health of pregnant women."

The health-care exception is crucial to abortion rights advocates and is considered a legal loophole by abortion opponents. By limiting the health exception to a "serious physical issue," Obama set himself apart from other abortion-rights proponents.

The official position of NARAL Pro-Choice America, the abortion-rights group that endorsed Obama in May, states: "A healthexception must also account for the mental health problems that may occur in pregnancy. Severe fetal anomalies, for example, can exact a tremendous emotional toll on a pregnant woman and her family."

The 1973 landmark abortion case, Roe v.Wade, established a right to an abortion, and a concurrent case, Doe v. Bolton, established that medical judgments about the need for an abortion could include physical, emotional and psychological health factors. "Senator Obama has consistently maintained that laws restricting abortions must contain exceptions for the health and life of the mother," Obama spokesman Tommy Vietor said Thursday. "Obviously, as he stated in the interview, he has consistently believed those exceptions should be clear and limited enough to ensure that they don't undermine the prohibition on late-term abortions."

Obama's position is similar to that taken by a bipartisan group of senators in 1998 who tried to counter efforts to ban certain late-term abortions with their own legislation. That proposal, which failed, would have banned all late-term abortions except for those that are necessary to protect the physical health of the mother.

In a statement, NARAL Pro-Choice said Obama's magazine interview is consistent with Roe v. Wade.

"Sen. Obama has consistently said he supports the tenets set forth by Roe, and has made strong statements against President Bush's Federal Abortion Ban, which does not have an exception to protect a woman's health," the organization's statement said.