When Sabrina Wang, a Chinese university student, saw an online post that claimed that manufacturers of sanitary pads had been cheating women, selling them pads that were significantly shorter than advertised, she decided to measure her own. She was shocked to find that all three brands she had at home were shorter than labeled, by as much as 17 percent.

“If I had issues when using them, I’d wonder if it was that I had gone too long without changing them,” Ms. Wang, 22, said. “It was only after everyone pointed it out that I realized it was a manufacturing problem.”

She wrote her own post, urging other women to lobby for stricter oversight of pad makers. “Manufacturers think we can’t go without their products because of our everyday physiological needs, so they dare to be so arrogant,” she said in an interview. “It’s a lack of respect.”

Ms. Wang was joining a chorus of voices in China that in recent weeks have demanded greater accountability from sanitary pad manufacturers and government regulators — and, more broadly, greater consideration of women. Criticism of the lengths of pads quickly expanded to scrutiny of their quality and price. From there, the conversation branched out to topics like inadequate sex education, body shaming and the lack of female corporate leaders.

Women have called for boycotts of brands they deem to be of subpar quality, and shared guides to making reusable pads at home. Dozens of hashtags about the topic, such as “black-hearted pads” and “Is it so hard for sanitary pad producers to meet women’s needs?” have trended online.

The backlash prompted one major manufacturer to pull all its products from the e-commerce platform Taobao, promising to improve them. State media outlets have denounced “deep-seated problems” in the industry. And a government-backed trade association promised to take public comments into account when formulating new regulations for sanitary products.