Menstrual cups have been heralded as a sustainable alternative to pads and tampons, and have been growing in popularity in recent years. But few studies have compared menstrual cups with these other feminine hygiene products in terms of their safety and effectiveness.
Now, a new review study has some good news for menstrual cup fans: The flexible cups that collect menses blood appear to be a safe option for managing periods, and they may be as effective as pads and tampons for preventing leakage.
The review authors also found that menstrual cup use didn't increase the risk of developing certain bacterial infections compared with use of other feminine hygiene products; and menstrual cups weren't detrimental to women's natural vaginal flora, another measure of safety. [7 Facts Women (And Men) Should Know About the Vagina]
Still, the review, published today (July 16) in the journal The Lancet Public Health, highlighted some aspects of menstrual cup safety that need more research. For example, the study authors could not determine whether menstrual cups were safer than tampons with regard to the risk of toxic shock syndrome (TSS) — a rare but life-threatening condition that's been linked with tampon use. Indeed, the authors identified several cases of TSS tied to menstrual cups, although the risk seems low, they said.
Overall, the results are reassuring about the safety of menstrual cups, said Dr. Jennifer Wu, an obstetrician-gynecologist at Lenox Hill Hospital in New York City, who wasn't involved with the review. But there is a need for more data on the rate of toxic shock syndrome among menstrual cup users, and how it can be prevented, she said.
For now, doctors generally recommend that menstrual cup users treat the product in a way that's similar to how they would use a tampon — removing and cleaning it every 8 hours or so.
"They do need to take it out regularly and wash it," Wu told Live Science. "This is not something you want to leave in for a day and a half."
There is also a question of whether women who use intrauterine devices (IUDs) for birth control may face an increased risk of IUD displacement when they use menstrual cups. More studies are needed to investigate whether this is a safe combination, the authors said.
Menstrual cups are typically bell-shaped and collect menses blood rather than absorb it, as tampons and pads do. The cups are often reusable, made from silicone, rubber or latex; and they can last up to 10 years. Although menstrual cups have been around since the 1930s, their popularity has spiked during the last decade, according to the BBC.
The new study is one of the first rigorous scientific reviews of menstrual cup use, the authors said. The researchers analyzed information from 43 previous studies on menstrual cup use involving more than 3,300 people from low-, middle- and high-income countries.
Four of the studies, involving about 300 people, directly compared leakage of menstrual blood during use of a menstrual cup, tampon or pad. In three of these studies, the amount of blood that leaked was similar among users of all three products; and in one study, menstrual cup users had less leakage than the others.
Among studies conducted in Europe, North America and Africa, there was no increased risk of infections of the reproductive tract, such as yeast infections, tied to menstrual cup use, compared with use of other menstrual products.
However, the researchers did identify five cases of toxic shock syndrome tied to menstrual cup use. The condition can occur when certain bacteria, particularly Staphylococcus aureus, grow rapidly in the vaginal tract and produce harmful toxins.
But because it's unclear how many women use menstrual cups overall, the researchers were not able to compare the rate of TSS among menstrual cup users to that of tampon users. The rate of TSS among menstruating women is about 1 in 100,000 women, Live Science previously reported.
The authors also identified 13 cases of women with IUDs that were dislodged when they used menstrual cups. This level of occurrence seems "pretty high," Wu said, but more studies are needed to examine this risk. Wu said she would advise women with IUDs to be "very careful" when using menstrual cups, and to check with their health care provider before using them. Still, Wu noted, some women who use IUDs don't get their period, meaning they wouldn't have a need for menstrual cups or other products for menstruation.
The review also found that a lot of women aren't aware of menstrual cups, with just 11% to 33% of women surveyed in high-income countries saying they knew about the products.
There also seems to be a "learning curve" of several months for women to become familiar with how to use them. But once women were familiar with the products, 70% said they wanted to continue to use the products to manage their period, according to the review.
What's more, the menstrual cups appeared to offer large cost savings and environmental benefits compared with pads and tampons. Evidence from the review suggested that, over a 10-year period, a single menstrual cup could cost about 5% to 7% of the cost of using pads or tampons. (For example, assuming that pads cost about 31 cents each, a woman who uses 12 pads per cycle would end up spending more than $480 over 10 years, while the average cost of a menstrual cup was about $23.)
The authors also estimated that, over a 10-year period, a single menstrual cup would create only 0.4% of the plastic waste generated by pad use and 6% of the plastic waste generated by tampon use.
The review "highlights the cost-effectiveness and lack of waste of the menstrual cup," Wu said.
She noted that there are different sizes and types of menstrual cups, and women may want to speak with their doctor about which type is best for their body.
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Originally published on Live Science.