In its first-ever ruling on "maternity harassment," the Supreme Court on Thursday nullified a lower court's decision to dismiss a physical therapist's claim that she was unjustly demoted on account of her pregnancy.

The term maternity harassment refers to various forms of workplace bullying involving pregnancy, which activists say remains a potent threat to women in Japan's male-dominated corporate world.

"The demotion caused a significantly negative impact on the plaintiff, who forfeited not only her managerial post but financial allowances" for which she was previously qualified, presiding Justice Ryuko Sakurai said in the ruling.