Democratic presidential front-runner Hillary Clinton has backed up her earlier statement that "the unborn person does not have constitutional rights," saying that even if the child is just hours away from delivery that child is still deprived of rights because "that is the way we structure it."

Speaking on ABC's "The View" on Tuesday, Clinton reaffirmed her support for the 1973 Roe v. Wade ruling that legalised abortion, calling it "an important statement about the importance of a woman making this most difficult decision with consultation by whom she chooses, her doctor, her faith, her family," LifeSite News reports.

"The View" co-host Paula Faris asked Clinton to clarify her position on the issue. "At what point does someone have constitutional rights, and are you saying that a child, on its due date, just hours before delivery still has no constitutional rights?" she asked.

"Under the law that is the case, Paula," Clinton answered.

Medical experts say weeks prior to birth, a preborn baby is already a completely formed human being with perfectly functioning brain, eyes, heart, and lungs. The baby is able to hear sounds from the outside world and recognises its mother's voice. The baby is also capable of surviving outside its mother's womb.

Critics immediately pounced on Clinton's remarks. "Clinton revealed that she believes no unborn child is subject to constitutional rights," the Republican National Committee said in a statement on Sunday when Clinton first made her position clear.

"Voters now know Clinton's extreme stance against the value of protecting life, and can no longer be misled by her deceptive pandering," the panel stated.

Meanwhile, a new poll released on Wednesday shows that Bernie Sanders is two points ahead of Clinton nationally (49-47) in the race for the Democratic presidential nomination.

The McClatchy/Marist poll was taken on March 31, even before Sanders' massive win in the Wisconsin primary on Tuesday, Newsmax reports.

Sanders has won the last six contests with victories in Idaho, Utah, Alaska, Hawaii, Washington State, and Wisconsin.

Because the Democratic delegates are allocated proportionately, Sanders won only 147 delegates to Clinton's 107 despite the Vermont senator's six straight wins.

Nevertheless, analysts say Sanders has a very good chance of passing Clinton among pledged elected delegates with 1,977 delegates remaining to be chosen.