There's an effective, environmentally friendly option for people with periods, and few know about it, research says

(CNN)They have been around since the 1930s, and still, many who menstruate are unaware of the alternative to pads and tampons: the menstrual cup.

They're safe and effective, and can save money and reduce waste and water usage, according to a study published Tuesday in the medical journal The Lancet Public Health, but they aren't well known among women.
"In any impoverished set of circumstances be it in Liverpool, or London, or anywhere in low-middle-income countries, people really struggle -- women and girls really struggle to be able to manage their menstruation," and menstrual cups can be a part of the solution, said Penelope Phillips-Howard, senior author of the study, which analyzed 43 international papers.
Menstrual cups "are incredibly, you know, good and useful and a product that has been under-recognized and under-valued," Phillips-Howard, a professor of public health epidemiology at the Liverpool School of Tropical Medicine, told CNN. "But beyond that is the bigger picture which is menstrual health, or menstrual hygiene -- it has been so neglected internationally."
    Menstruation is part of life for 1.9 billion girls and women across the globe. When women can't afford adequate menstrual products, something referred to as period poverty, they suffer serious consequences, like missing out on school.
    If women resort to using poor quality sanitary products, it can increase their risk of infections, says the study. Girls in low-middle-income countries report using materials like cloths, cotton wool, tissue paper or disposable pads to manage their periods, the study said.

    How menstrual cups compare

    Menstrual cups are inserted into the vagina when a woman is menstruating, but fluid is collected in a cup, rather than absorbed. Cups should usually be emptied every six hou