Menstrual Cups

Alongside the documented rise and fall of civilizations, there is the history of the menstruating woman and her poisonous touch. In 77 AD, Pliny the Elder’s recording of “facts connected with menstrual discharge” included its power to neutralize “all spells of magicians” and deliver “fatal effects to the man”.^[3] These beliefs carried over into the 1900s, during which time scientific journals (including The Lancet) published studies and editorials debating the existence of “menotoxin”, a poison excreted through the blood and skin of women during menstruation. Menstruating women were thus told to abstain from social gatherings and household chores or face “baked bread collapsing and permanent hair waves drooping”.^[4]

Thankfully, the stigmas surrounding menstruation are falling away in many areas of the world, allowing a diverse range of menstrual management options to rise (along with the bread) to the surface. These options include sanitary pads, tampons, discs, and cups, all of which empower people to go about their daily activities and attend school/work without “fatal effects”.

Menstrual cups, in particular, are a topic of increased interest. Reusable and affordable, they sound like a new trend, but they actually first hit the market in 1937. Studies done at the time indicated they were well tolerated, safe, and potentially advantageous.^[5][6] However, the majority of women didn’t feel comfortable using them. Cups were considered somewhat scandalous and unclean (many women were unwilling to even touch their vaginal tissues), and the original models were “bulky” and “messy”.^[2] Plus, the latex rubber shortage of World War II temporarily halted their production.

Years later, the menstrual cup was improved and reintroduced, but it remains a lesser known option. Recent interviews in high-income countries report that only 11–33% of women are aware of the cup, and out of 69 websites on puberty and menarche education across 27 countries, only 21 (30%) mentioned menstrual cups, while disposable pads were mentioned by 53 (77%) and tampons by 45 (65%).^[7][8][9] It is time to let the research on menstrual cups ring loud and clear, so cozy up with a cup of…coffee or tea and read away to get a handle on it all!

Historically, menstruation was misunderstood, and management options were duly limited. As the taboos associated with menstruation lessened, menstrual care options increased, one being the menstrual cup. Introduced in 1937, the cup was generally well tolerated and appeared safe, but it remains a lesser known option to this day. There is a need for increased awareness of the menstrual cup’s benefits and shortcomings to help people make informed decisions about menstrual management.

There are two forms of menstrual cups, vaginal and cervical, with the latter more commonly known as a menstrual disc and rarely referred to as a cup. Vaginal menstrual cups are small, flexible, bell-shaped cups which are inserted into the vagina to catch and collect blood, rather than absorbing it like a pad or tampon. When properly inserted, the cup sits in the vaginal canal below the cervix, where a seal is created between the cup’s rim and the vaginal wall. Blood then flows down into the cup, and blood flow outside of the vagina is prevented.

The vaginal cups are made of medical-grade silicon, rubber, latex, or elastomer and are reusable for up to 10 years.^[7] They also come in a variety of colors, sizes, shapes, firmness levels, and handle choices to help satisfy a broad range of user needs and preferences, including shorter cups for a “low cervix”, larger cups for a heavier flow or for those who have given birth vaginally, and firmer cups for users with higher activity levels. After all, vaginas and lifestyles differ and so too must the cup.

A vaginal menstrual cup remains inserted for 4 to 12 hours (depending on the flow rate and cup size), at which time it is removed, emptied, cleaned, and reinserted. Prior to insertion, the cup is folded (per user preference) to fit inside of the vaginal canal, and the fold is released once the cup is in place. Removal varies somewhat depending on the type of cup used, but the majority require breaking the “seal” by pinching the bottom of the cup first and then removing it. Between cycles, menstrual cups should be sanitized by submerging them in boiling water for 5 minutes (time varies by brand).

While similar in function, a menstrual disc/cervical cup has a few distinct differences from a vaginal menstrual cup. The disc is (no surprise) shaped like a disc, with a firm but flexible outer rim and a softer interior for blood collection. Some are made of silicone and are reusable, but others are made of BPA free polymer and are disposed of after each use (generally 12 hours). Anatomically, the disc rests in the vaginal fornix at the base of the cervix (higher up than a vaginal cup). It is held in place by the pubic bone, under which the rim is tucked, as well as the vaginal muscles. To remove the disc, a finger is hooked under the rim, and the disc is pulled forward until it exits the vagina while keeping it parallel to prevent spillage.

Menstrual cups come in two forms: vaginal and cervical. The term “cup” usually refers to the vaginal form, while “disc” is used for the cervical form. During menstruation, the menstrual cup is inserted into the vagina, where it collects blood for 4 to 12 hours (depending on flow rate and cup size). The vaginal cup is emptied and cleaned out between insertions and sanitized (in boiling water) between cycles. One vaginal cup can last up to 10 years. Discs, on the other hand, may be either disposable or reusable.

A recent systematic review and meta-analysis of 43 studies (27 on vaginal cups, 5 on cervical cups, and 11 mixed/unknown) concluded that cups are an acceptable and effective option for menstrual care in countries of low, middle, and high income.^[7] The primary outcome used to determine menstrual cup efficacy was menstrual blood leakage while using the cup for at least three cycles. A total of 4 studies (293 participants) compared cups directly to pads/tampons using this outcome. In 3 studies, leakage was reported as comparable between methods.^[10][11][12] In a randomized crossover trial (110 participants), cup use resulted in higher satisfaction for convenience and leakage compared to tampon use, with 91% of participants stating they would continue to use the cup and recommend it to others.^[13]

There are 7 studies (934 participants) using currently available menstrual cups in which leakage was reported as a proportion of users. The proportion of leakage was 2% in 3 studies (293 participants),^[14][15][16] 3% in 1 study (106 participants),^[10] 6% in 1 study (33 participants),^[15] 12% in 1 study (119 participants),^[17] and 31% in 1 study (383 participants).^[2] Some of the reasons for leakage included menorrhagia (abnormally heavy or prolonged bleeding), unusual uterus anatomy, improper cup size or placement, and infrequent cup changes. The study with the highest leakage percentage (31%) examined cervical cups (menstrual discs), and the majority of leakage was rated as occasional. At study end, 37% found the cervical cup to be better than, 29% worse than, and 34% equivalent to using pads/tampons. When including postmarking surveillance data, leakage was the most common complaint submitted to the manufacturer (168 complaints from 2003 to 2008) and was a reason for discontinued use.^[2]

Interestingly, menstrual cups are sometimes used outside of their traditional indication. They have successfully collected genital specimen samples for HIV patients,^[18] determined normative ranges of menstrual fluid volume,^[19] and reduced urinary leakage and improved quality of life in people with vesicovaginal fistulas.^[20][21]

In studies using a currently available menstrual cup, leakage is reported in 2–31% of female participants over the course of at least 3 menstrual cycles. Reasons for leakage include user errors (improper cup size or placement and too few cup changes), as well as non-modifiable factors (menorrhagia and unusual uterus anatomy). Overall, leakage with the cup is reported as similar or better than prior methods, though (in some cases) leakage is the reason for cup discontinuation.

Menstrual cups come with a learning curve, and initial apprehension is frequently reported by first-time cup users. Qualitative studies capture concerns such as fear related to the cup’s size and the possibility of pain and reproductive harm.^[7] Some of these concerns do indeed affect cup usability. Quantitative studies find a small percentage of participants (2.8% across 11 studies; 1251 participants) cannot even insert the cup, 9.3% (7 studies; 461 participants) have trouble removing the cup, and 10.7% (10 studies; 1190 participants) find the cup troublesome enough to stop using it all together.^[7]

Despite these challenges, the majority of people who continue using menstrual cups beyond their first cycle experience fewer cup-related difficulties in later cycles as they grow more accustomed to its use. This is reflected well by comparing study outcomes based on duration of cup use. In 5 studies (272 participants), 35.3% found cup insertion difficult during the first cycle, as opposed to 13.0% (12 studies; 789 participants) during later cycles. Similarly, 32.9% of participants (3 studies; 221 total participants) experienced discomfort when wearing the cup during the first cycle, but 7.9% (9 studies; 737 participants) experienced discomfort in later cycles.^[7] One randomized controlled trial, which compared a tampon group to a cup group, found that the tampon group’s satisfaction declined overtime, while the cup group’s satisfaction had an initial drop followed by an increase.^[13] However, it is still more likely that cup users will experience pain when compared to pad users, even after 3 months.^[10]

In 15 studies, the participants were asked if they would continue to use a menstrual cup. When the results were pooled, 73% reported willingness to keep using the cup after the study ended. Reasons for continued use included less concern over leakage, fewer changes per cycle, improved mobility, reduced odor, lower long-term costs, and perceived environmental friendliness compared to previous methods.^[7] Reasons for discontinued use (outside of adverse events) included leakage, discomfort, continued difficulty with insertion/removal, messiness, and poor fit.^[7][12][22] Privacy was another challenge for continued use, particularly among adolescents using public restrooms and users in low-income countries, as the cup must be emptied into a toilet and rinsed with water before reinserting. Hence, peer support is important for continued cup use.^[7] In a study of 192 adolescents, self-reported cup use increased over time with the help of peer-to-peer mentorship.^[23]

Menstrual cups come with a learning curve and may be difficult to insert and remove, uncomfortable to wear, and quite messy for the first few cycles. After three cycles, the majority of users are able to familiarize themselves with the cup and experience fewer cup-related issues. In fact, 73% of participants who use a cup in a study report willingness to continue using one.

Consistent use of a vaginal menstrual cup is less costly than using tampons and/or pads, and it also reduces plastic waste. Using 10-year estimates, a vaginal cup costs 5% of total pad costs and 7% of total tampon costs. Furthermore, a vaginal cup generates 0.4% and 6% of the plastic waste produced by pads and tampons, respectively.^[7]

In the long term, vaginal menstrual cups are a more cost-effective solution to menstrual management and generate less plastic waste.

For many people who face socioeconomic and/or cultural barriers to accessing menstrual products, poor menstrual care negatively affects physical and mental health. The inability to afford or access menstrual care products may lead to missed school days and infections from old cloths used as makeshift pads.^[24] Transactional sex is commonly used to obtain necessary care products. This is a very high price to pay, as it carries a risk for contracting a sexually transmitted infection (STI) or becoming pregnant, notwithstanding the emotional costs.

Vaginal menstrual cups offer a potential solution to this issue. A one-time distribution of a vaginal cup provides years of menstrual care. In a study in rural Kenya, provision of vaginal menstrual cups to adolescents was associated with a lower risk for STIs and bacterial vaginosis, though these findings are limited by a lack of baseline testing. Conversely, school dropout rates were not affected.^[24] In a study done in Nepal, the distribution of vaginal cups to adolescents did not significantly improve school attendance, test scores, or self-esteem, but it did reduce time spent on laundry (no rags to wash) and allowed them to easily “forget” about their period.^[25] In Uganda, public health organizations report that providing people with vaginal cups leads to improved quality of life and a reduction in menstrual taboos.^[26]

Importantly, vaginal menstrual cups require access to clean water and privacy for removal. These physical aspects of menstrual care are estimated to be inaccessible to at least half a billion people worldwide, leaving them unable to manage their menstruation with dignity and cleanliness.^[27] In these areas, menstrual cups are especially challenging to use, as cups need to be cleaned and are not disposed like pads or tampons. Some circumvent this issue by carrying a bottle of water with them to clean their cup,^[10] but this is not always possible.

Menstrual management is a public health issue, as many people do not have easy access to menstrual care products. In certain areas, the provision of vaginal menstrual cups substantially improves physical and mental health.

As the menstrual cup is considered a medical device, adverse events and complaints related to its use are submitted to the FDA and recorded in the Manufacturer and User Facility Device Experience (MAUDE) database. This database contains both mandatory reports (from manufactures, importers, and device user facilities) as well as voluntary reports (from health care professionals, patients, and consumers). If you are interested in viewing the reports related to menstrual cups, you can search the database directly or use this link.

To date, three studies on menstrual cups included vaginal examinations. Use of a menstrual cup was not associated with any changes in vaginal or cervical epithelium.^[7]

Vaginal wounds were reported in three case reports, though there are no medical records to confirm these events.^[7] One report was documented in a study during postmarketing surveillance. The woman stated that the cervical cup “wore through her vaginal wall”, necessitating surgery.^[2] Two more are documented in MAUDE. There is a self-report from a woman stating the cup gave her a wound, and another from a woman who went to the ER for cup removal, where it was discovered that the cup’s stem was irritating the stitches from her post-childbirth tear site. ^{[28] [29]}

In certain cases, removal of the cup becomes difficult enough to necessitate professional assistance. One case study reported on a 20-year-old woman whose cup became lodged within her cervix. Ultimately, removal in the Emergency Department was successful, and, although there was some cervical inflammation present, no long-term damage was reported.^[30] Further incidents are documented in MAUDE, where over 80 “difficult to remove” events are recorded. The precise reason for this issue is not always clear, but improper cup sizes and broken stems are sometimes cited as the cause.^[31]

While it isn’t extremely common, there are situations in which professional help is required for menstrual cup removal. Choosing an appropriate cup size with a sturdy stem may lower the risk of this adverse event.

In MAUDE, there are over 5 self-reports of infections while using a menstrual cup, including yeast infections and urinary tract infections. However, clinical trials find no association between menstrual cup use and an increased risk for infection, either in the reproductive tract or systemically.^[7] For example, a study in Kenya, which compared menstrual cups, pads, and usual practice, reported no difference in reproductive tract infections between groups.^[24]

Menstrual cups do not appear to increase the risk of developing reproductive or systemic infections compared to other methods of menstrual care.

Toxic shock syndrome (TSS) is a rare, life-threatening condition in which the body’s response to toxins emitted by bacteria result in high fever, low blood pressure, rashes/skin peeling, and/or signs of multiorgan involvement (e.g., flu-like symptoms). While it can occur in people across genders and age groups, TSS became associated with menstruation and high-absorbency tampon use following a number of case reports in the 1980s. It was postulated that certain tampons created an environment favorable to bacterial growth by allowing blood to accumulate within the tampon’s fibers, increasing vaginal pH, and introducing oxygen into the vaginal canal. After the FDA mandated certain regulations on tampon production, there was a nationwide decline in TSS cases.^[32] Nevertheless, menstruation continues to be an important risk factor for TSS, with nearly twice as many reported menstrual cases compared to nonmenstrual cases in a recent U.S. population-based study. Still, at 0.69 incidences per 100,000 people, it remains largely uncommon.^[33]

As such, the propensity for menstrual cups to lead to TSS is an ongoing surveillance project. Cups may not absorb vaginal fluids or disturb the vagina’s pH,^[2] but this does not mean they carry no risk for TSS. In an in vitro study evaluating the ability of a silicon vaginal cup to promote proliferation of Staphylococcus aureus (the bacteria often responsible for TSS), a biofilm formed on menstrual cups when they were bathed in a growth medium. Additionally, the use of larger cup sizes increased the bacteria’s production of harmful toxins, likely due to greater aeration of the medium upon cup insertion. The authors advised boiling the cup between uses and choosing smaller cup sizes to mitigate possible TSS risks.^[34]

In clinical studies, toxic shock syndrome was associated with menstrual cup use in five case reports. Only one case provided direct microbiological confirmation by menstrual cup culture, while the cause in the other cases is less certain.^[7] Two of the cases involved a concomitant device (intrauterine device IUD) and another involved a patient with immunodeficiency disease.^[2][35] Outside of case reports, one study of 604 adolescents in western Kenya was designed to detect TSS risks. It reported no TSS cases over 10.9 months of menstrual cup use.^[14]

The risk of toxic shock syndrome (TSS) while using a menstrual cup is low. Keeping the cup clean, washing hands before cup insertion and removal, and potentially using a smaller cup may reduce the risk of TSS.

When considering IUD expulsion, it is important to first understand the prevalence of this event. IUD expulsion occurs in approximately 2% to 10% of IUD users, often without a specific incentive event. Risk factors are not fully understood but may include age (possibly higher among younger users), a history of heavy periods, the type of IUD used, how recent the placement occurred (expulsion is more common in the first year), previous IUD expulsions, and IUD placement in the immediate postpartum period (particularly after a vaginal birth).^[36][37][38]

There are case reports of IUD dislodgement during menstrual cup use. This is possibly related to the suction of vaginal cups and/or accidental IUD string pulling while removing menstrual cups. In a case series of 7 cup users with IUD expulsion, 4 specifically reported accidently pinching, pulling, or “suctioning” their IUD strings while removing the cup. All but one of the women had their IUD reinserted, but only 2 stopped using menstrual cups (one of whom went on to experience another expulsion). Upon reinsertion, 2 women had their IUD strings cut shorter and continued to use cups with no reported IUD issues. A third experienced two cup-related expulsions before selecting implant contraception.^[39]

In a retrospective chart review, IUD expulsion rates at less than 6 weeks after IUD placement did not differ significantly among women who used pads, tampons, or menstrual cups.^[37] Conversely, a survey of IUD users did find an association between concurrent cup and IUD use and IUD expulsions. Compared to tampon and pad users, cup users experienced significantly higher IUD expulsion rates, though only one person reported the expulsion occurred while using the cup. Others believed their IUD expulsion was related to sexual activity, menstruation (without cup use), or tampon use rather than cup use. Thus, it is unclear whether the cup contributes to IUD descent and expulsion, and further research in this area is needed.^[40] Possible ways to mitigate this risk include having a doctor cut the IUD strings flush with the cervix (although this can increase the risk of a difficult IUD removal) and carefully breaking the seal prior to removing a vaginal cup while feeling for any strings before pulling.^[39]

There is no clear evidence on whether or not menstrual cups increase the risk of IUD expulsion. However, it is possible to accidentally pull or suction IUD strings while attempting to remove a menstrual cup. If you plan to use a cup along with an IUD, be sure to break the seal before removing the cup and feel for any strings prior to pulling the cup out. Talk to your gynecologist about possibly shortening your IUD strings, but keep in mind this could make removal of your IUD more difficult in the future. Also, be aware of the warning signs of IUD expulsion.

The vagina is anatomically close to the bladder, and the ureters pass closely to the lateral vaginal wall. Consequently, improper cup placement in the vaginal canal presents the possibility of placing pressure on the ureters and bladder. In fact, there are three case reports on hydronephrosis (swelling of a kidney due to build-up of urine) related to cup use. All three cases involved a woman presenting to the emergency department with renal colic, the discovery of an improperly positioned cup in the vagina, and immediate relief of symptoms upon cup removal.^[41][42][43] While this complication is rare, awareness and recognition are important for all cup users.

Four cup-related adverse events were possibly due to an allergy. In one case report, a silicone allergy resulted in a severe reaction and reconstructive vaginal surgery.^[44] In another case, a woman reported continued irritation while using the cup and was told by her doctor that she might be allergic to its material.^[45] The final two allergic cases were reported in a study during active postmarketing surveillance.^[22]

Lastly, there is a report of one woman who, after four years of regular cup use, developed endometriosis and adenomyosis.^[46] It was proposed that this might be related to retrograde blood flow caused by the cup, but the FDA rejected this assertion and deemed it implausible. There are no other reported cases of this adverse event.

Two rare adverse events related to menstrual cup use include hydronephrosis and allergic reactions. The former is due to improper cup placement and may be avoided by good insertion techniques. The latter highlights the importance of knowing what you are allergic to and avoiding cups containing those allergens. If you are unaware of any allergies but continue to feel irritation during cup use, consider trying one made of different materials.