Retiring Justice Sandra Day O'Connor, known as a swing voter on abortion rights, wrote the court's opinion in what could be her last ruling.
"Making distinctions in a murky constitutional context, or where line-drawing is inherently complex, may call for a 'far more serious invasion of the legislative domain' than we ought to undertake," O'Connor wrote, according to the Associated Press.
O'Connor joined other justices in their opinion that the lower court went too far in blocking the 2003 New Hampshire law.
In making the rare 9-0 ruling on Wednesday, the Supreme Court avoided having to make a major ruling on the controversial abortion issue.
The case will now return to 1st U.S. Circuit Court of Appeals in Boston, the court that struck down the law, for reconsideration, the AP reported.
Twenty four states require a parent's approval in cases of minors having abortions. In 19 states, including New Hampshire, parental notification is required.
The Supreme Court was asked to consider whether New Hampshire's law, which does not include an exception for medical emergencies, placed an "undue burden" on women.
By sending the case back to the lower court, the justices avoided answering that question.
"In the case that is before us...the lower courts need not have invalidated the law wholesale," O'Connor wrote in her opinion. "Only a few applications of New Hampshire's parental notification statute would prevent a constitutional problem."
Wednesday's ruling is considered a victory for New Hampshire and for anti-abortion groups.
Former New Hampshire state Rep. Phyllis Woods, one of the main sponsors of the parental notification law, said she was pleased with the outcome, the AP reported.
"Our concern has always been that a blanket health exception opens the door and really negates the whole purpose of the bill."