Table 2.
Safety and side-effects of the menstrual cup
| n (%) or description | Notes | Data source | ||
|---|---|---|---|---|
| Handling and positioning of menstrual cup | ||||
| Vaginal wound | ||||
| Cup not clear (Divacup or softcup) | Event April, 2012; vaginal wound due to use of menstrual cup, needing treatment from physician for vaginal bleeding | Complete medical records were not available for evaluation | FDA database14 | |
| Softcup (cervical) | Reported April, 2012; long-term customer of softcup product claimed vaginal scarring due to use | Medical director did not find anything in medical records provided by customer related to vaginal health | FDA database14 | |
| Softcup (cervical) | FDA database case report: “…cup wore through the vaginal wall, damaging an artery that required surgical repair” | Event could not be confirmed; no medical records were available | North et al (2011)13 | |
| Vaginal pain on removal | ||||
| Divacup (vaginal) | Event March, 2017; extreme pain on removal (first use), individual stopped using the cup | Self-report; no medical report available | FDA database14 | |
| Pelvic pain | ||||
| Softcup (cervical) | Event February, 2017; pain in lower pelvis and rectum and nausea about 1 h after insertion, no longer present approximately 30 min after removal | Self-report; no medical evaluation available; individual stopped use after trying twice (possibly vascular compression) | FDA database14 | |
| Vaginal irritation | ||||
| Gynaeseal (cervical) | One (1%) of 73 | Self-report by participant | Cattanach et al (1991)39 | |
| Cervix irritation | ||||
| Menses cup (vaginal) | One (2%) of 51 | Cervical smear was normal | Cheng et al (1995)41 | |
| Allergy and rash | ||||
| NR, vaginal cup | Allergy: one (1%) of 150; and rash: two (1%) of 150 | · · | Kakani et al (2017)48 | |
| Softcup (cervical) | FDA database: two case reports | NR | North et al (2011)13 | |
| Mooncup (vaginal) | Event 2010: silicone allergy in one individual | Surgery was needed for vaginal repair; manufacturer noted that silicone allergy is very rare | FDA database14 | |
| Difficulty with removal requiring professional assistance | ||||
| Gynaeseal (cervical) | One (5%) of 22 | · · | Gleeson et al (1993)46 | |
| Softcup (cervical) | FDA database: three case reports reported by North 2011; one event in 2018 | · · | North et al (2011),13 FDA database14 | |
| Softcup (cervical) | Reported complaints to company 2003–08: 42 individuals underwent physician-assisted removal | Other complaints reported to company included poor fit (n=102), leakage (n=168), messy (n=98) | North et al (2011)13 | |
| Mooncup (vaginal) | Case report: menstrual cup lodged on cervix, difficult to remove, requiring assistance | Moderate cervical inflammation after retrieval | Day et al (2012)63 | |
| Divacup (vaginal) | Event April, 2015: one case report required an emergency room visit for removal | · · | FDA database14 | |
| Reproductive tract observations with use of menstrual cup | ||||
| Vulva abnormalities | ||||
| Softcup (cervical) | Baseline: four (1%) of 393; cycle 1: eight (2%) of 365; cycle 2: six (2%) of 326; cycle 3: five (2%) of 305 | Vulva-vaginal inspection at baseline and monthly for 3 months; no p values reported | North et al (2011)13 | |
| Abnormalities of vaginal wall | ||||
| Softcup (cervical) | Zero of 44 | Vulva-vaginal inspection at baseline and monthly for 3 months | North et al (2011)13 | |
| Tassette (vaginal) | Zero of 12 | Vaginal inspection after 3 months | Pena et al (1962)52 | |
| Tassette (vaginal) | Zero of 50 | Vaginal inspection done; timing of inspections not clear | Karnaky et al (1962)70 | |
| Abnormalities of cervix | ||||
| Softcup (cervical) | Baseline: 23 (6%) of 390; cycle 1: ten (3%) of 345; cycle 2: six (2%) of 326; cycle 3: four (1%) of 300 | Inspection of cervix; no p values reported for differences | North et al (2011)13 | |
| Softcup (cervical) | Abnormal cervical smear test: baseline: one (<1%) of 406; cycle 1: one (<1%) of 368; cycle 2: two (1%) of 329; cycle 3: zero of 308 | Abnormal cervical smear test results were exclusion criteria at admission, and a reason for discontinuation of the study; no p values reported for differences | North et al (2011)13 | |
| Condition of vaginal and cervical epithelium | ||||
| Softcup (cervical) | 44 women examined at baseline, 37 at 2–3 months, and 25 at 5–6 months | “The Softcup caused no alteration or disruption in vaginal or cervical epithelium, as assessed by colposcopy and cervical cytology” | North et al (2011)13 | |
| Vaginal flora and infections with use of menstrual cup | ||||
| pH changes of vagina | ||||
| Tassette (vaginal) | Zero of 50 | No abnormalities, vaginal areas where menstrual cup was placed were more acid | Karnaky et al (1962)70 | |
| Softcup (cervical) | Mean pH at baseline: 4·6 (n=400); cycle 1: 4·6 (n=368); cycle 2: 4·6 (n=329); cycle 3: 4·5 (n=308) | No p values reported | North et al (2011)13 | |
| Clue cells (vaginal smear) Lactobaccilus | ||||
| Softcup (cervical) | Number with clue cells: baseline n=6; cycle 1 n=6; cycle 2 n=2; cycle 3 n=4 | Sample sizes and p values were not reported | North et al (2011)13 | |
| Lactobaccilus | ||||
| Softcup (cervical) | “…before, during, and after use of the cup, vaginal Lactobacillus (normal vaginal flora) was maintained at normal levels.” | Data in figure 3 in publication cannot be extracted; no significant changes according to authors | North et al (2011)13 | |
| Gardnerella vaginalis | ||||
| Softcup (cervical) | No significant changes from baseline-cycle 3 according to authors | Data in figure 3 in publication cannot be extracted | North et al (2011)13 | |
| Bacterial vaginosis | ||||
| Softcup (cervical) | No significant changes from baseline to cycle 3 according to authors | Data in figure 3 in publication cannot be extracted | North et al (2011)13 | |
| Mooncup (vaginal) | Study end survey: cup 21 (15%) of 144; pads 40 (20%) of 202, and usual practice (control) 32 (21%) of 156; cup vs control p=0·11 and cup vs pads p=0·13; among girls enrolled for ≥9 months: cup 13 (13%) of 101, pads 29 (20%) of 143, usual practice 20 (19%) of 104; cup vs control p=0·07, and cup vs pads p=0·018 | Cluster randomised trial of schools; median follow-up 11 months (range 3–15) | Phillips-Howard et al (2016)5 | |
| Candidiasis | ||||
| Softcup (cervical) | Number with candidiasis: baseline n=6; cycle 1 n=6; cycle 2 n=3; cycle 3 n=6 | Sample sizes not reported; according to authors, yeast decreased significantly from month 1 to 2 | North et al (2011)13 | |
| Ruby cup (vaginal) | Zero of 18 participants had vaginal candidiasis at follow-up (3–5 months) | NA | Tellier et al (2012)56 | |
| Tassette (vaginal) | Candida albicans decreased with the use of the cup | NR | Karnaky et al (1962)70 | |
| Mooncup (vaginal) | Study end survey: cup 11 (8%) of 143, pads 19 (10%) of 200, usual practice (control) 13 (9%) of 156; cup vs control p=0·87, and cup vs pads p=0·68 | Cluster randomised trial of schools; median follow-up 11 months (range 3–15) | Phillips-Howard et al (2016)5 | |
| Group B Streptococcus | ||||
| Softcup (cervical) | No differences between baseline and cycle 1 to cycle 3 | Data in figure 3 in publication cannot be extracted; no significant changes according to authors | North et al (2011)13 | |
| Enterococcus | ||||
| Softcup (cervical) | Increase in Enterococcus from cycle 2 to cycle 3 (p=0·03) | “… this increased frequency persisted for 3 months after discontinuing use of the cup, suggesting that factors or behavior other than cup use may have influenced colonization”; data in figure 3 in publication cannot be extracted | North et al (2011)13 | |
| E coli | ||||
| Softcup (cervical) | No significant changes from baseline to cycle 3 according to authors | Data in figure 3 in publication cannot be extracted | North et al (2011)13 | |
| Escherichia coli on menstrual cup | ||||
| Mooncup (vaginal) | Nine (53%) of 17 if used cup for <6 months; four (22%) of 18 if used for ≥6 months (p=0·12); association between E coli with heavy periods: 61·5% of girls reporting heavy periods had E coli on cups, compared with 22·7% of those stating they did not have heavy periods (p=0·022, no numbers presented) | Cluster randomised trial of schools; median follow-up 11 months (range 3–15) | Juma et al (2017)29 | |
| Chlamydia trachomatis | ||||
| Mooncup (vaginal) | Study end survey: cup three (2%) of 144, pads three (2%) of 201, usual practice (control) seven (5%) of 154; cup vs control p=0·20, and cup vs pads p=0·63 | Cluster randomised trial of schools; median follow-up 11 months (range 3–15) | Phillips-Howard et al (2016)5 | |
| Trichomonas vaginalis | ||||
| Softcup (cervical) | Zero cases at baseline, and cycles 1 to 3 | Sample sizes not reported | North et al (2011)13 | |
| Mooncup (vaginal) | Study end survey: cup two (1%) of 143, pads five (3%) of 200, usual practice (control) seven (5%) of 154; cup vs control p=0·12, and cup vs pads p=0·36 | Cluster randomised trial of schools; median follow-up 11 months (range 3–15) | Phillips-Howard et al (2016)5 | |
| Ruby cup (vaginal) | Zero of 18 at baseline, and at 3–5 months of follow-up | NA | Tellier et al (2012)56 | |
| Neisseria gonorrhoea | ||||
| Mooncup (vaginal) | Study end survey: cup one (1%) of 144, pads one (1%) of 201, usual practice (control) one (1%) of 154; cup vs control p=0·96, and cup vs pads p=0·81 | Cluster randomised trial of schools; median follow-up 11 months (range 3–15) | Phillips-Howard et al (2016)5 | |
| Ruby cup (vaginal) | Zero of 18 at baseline, and at 3–5 months of follow-up | NA | Tellier et al (2012)56 | |
| Staphylococcus aureus | ||||
| Softcup (cervical) | No significant changes in cycles 1–3 compared with baseline | Data in figure 3 of publication cannot be extracted | North et al (2011)13 | |
| Mooncup (vaginal) | Among menstrual cup users: four (11%) of 38 in first month of intervention, 13 (9%) of 139 after first month; p=0·83 (median follow-up 4 months, range 2–11 for this substudy); prevalence was 21 (11%) of 197 in sanitary pads group, and 16 (11%) of 153 in usual practice group | Cluster randomised trial in schools; median follow-up 11 months (range 3–15); samples from vaginal swab (self-swabbing) | Juma et al (2017)29 | |
| be'Cup (vaginal) | Silicone cup: potentially more S aureus after incubation for 8 h with shaking in a plastic bag with S aureus in one of two cups used, but not when no shaking | In-vitro study | Nonfoux et al (2018)73 | |
| Me Luna (vaginal) | Thermoplastic isomer cup: no more S aureus after incubation for 8 h with shaking in plastic sac, and not when no shaking | In-vitro study | Nonfoux et al (2018)73 | |
| TSST-1 | ||||
| Mooncup (vaginal) | 49 schoolgirls with vaginal S aureus had second swab: ten yielded S aureus, two had TSST-1, both in sanitary pad group; the cases were asymptomatic | Cluster randomised trial in schools; median follow-up 11 months (range 3–15); sample from vaginal swab (self-swabbing) | Juma et al (2017)29 | |
| NR | No TSST-1 in supernatant of S aureus cultivated for 24 h (incubated aerobically in a still growth environment) in the presence of elastic polymer menstrual cup (n=16 menstrual cups) | In-vitro study | Tierno et al (1989)71 | |
| Tassaway (vaginal) | S aureus MN8 produced no TSST-1 when grown in the presence of Tassaway (elastomeric polymer, n=6), washed or unwashed, no shaking, incubation overnight | In-vitro study | Tierno at al (1994)72 | |
| be'Cup (vaginal) | Silicone cup: potentially more TSST-1 production after incubation for 8 h with shaking in plastic bag with S aureus compared with control, but not when not shaken or with pieces of cup | In-vitro study | Nonfoux et al (2018)73 | |
| Me Luna (vaginal) | Thermoplastic isomer cup: potentially more TSST-1 production after incubation for 8 h with shaking in plastic bag with S aureus compared with control, but not when not shaken or with pieces of cup | In-vitro study | Nonfoux et al (2018)73 | |
| TSS | ||||
| Mooncup (vaginal) | Zero of 192 in trial in Kenya | “Safety monitoring components comprised routine nurse-based screening, population-based monitoring (school and community) and clinical evaluation of infection with laboratory confirmation” | Juma et al (2017)29 | |
| Softcup (cervical) | Two case reports in the FDA database | Both unconfirmed cases of TSS | North et al (2011)13 | |
| Divacup (vaginal) | One case report: blood cultures and urine culture negative, no culture of the menstrual cup was done | Woman had history of Hashimoto's thyroiditis and chronic menorrhagia | Mitchell et al (2015)66 | |
| Mooncup (vaginal) | Event February, 2012: TSS 2 days after using of first and new Mooncup resulting in 9 days of inpatient hospital stay; vaginal swab positive for S aureus | Had an IUD, Mooncup was not sent for bacteriological testing | FDA database14 | |
| Divacup (vaginal) | Event February, 2015: TSS from Streptococcus resulting in 5 days of i-patient hospital stay; culture of cup isolated group A and B streptococcus | Woman had used Divacup for menstrual period, which started 3 days before illness; menstrual cup was in for 18 h on admission to hospital | FDA database14 | |
| UTI | ||||
| Ruby cup (vaginal) | Baseline: four (13%) of 31; at follow-up (after 3–5 months) three (17%) of 18; p=0·65, McNemar test | One participant with a UTI at enrolment and follow-up had her cup stolen and used toilet paper in vagina as a tampon | Tellier et al (2012)56 | |
| Gynaeseal (cervical) | One (1%) of 73 had transient dysuria | “The woman who developed dysuria did not seek treatment and the problem subsided within 24–48 hours” | Cattanach et al (1991)39 | |
| Softcup (cervical) | Urine analysis done; detailed results not reported | “Monthly monitoring of gynecological health via urinalysis, pelvic examination with visual evaluation of tissues, vaginal pH, and microscopic wet mount showed no adverse effects of cup use” | North et al (2011)13 | |
| Softcup (cervical) | Event August, 2014: UTI confirmed by urine cultures twice after use of softcup | Medical records were not available for evaluation | FDA database14 | |
| Infections overall | ||||
| Tassette (vaginal) | “The amount of bacterial contamination was greatest with the pad, next with the tampon and least with the rubber cup” | No data provided; study reported to make cultures from vaginal wall samples and to examine fresh and stained smears for C albicans, Trichomonas vaginalis, Haemophilus vaginalis, and for predominance of Gram-positive or Gram-negative cocci, small rods or long-rod bacilli (Doederlein bacilli) | Karnaky et al (1962)70 | |
| Softcup (cervical) | FDA database: one case report | Vaginal infection not further specified; could not be confirmed at follow-up | North et al (2011)13 | |
| Butterfly cup (vaginal) | “…none of the women sought treatment for a pelvic infection. There was no onset or worsening of dysmenorrhoea in 83%, dyspaurenia in 94%, pelvic pain in 92% and vaginal discharge in 92% of the participants during the 12 months of cup use”; n=52 | NA | Madziyire et al (2018)49, 50 | |
| Gynaeseal | “There was no increased pathogenicity detected in vaginal flora. There was a trend towards smaller numbers of potentially pathogenic bacteria for 4 of the women, and the remaining woman showed no change. None of the women developed any significant medical problems” | Vaginal swabs before and after use, five women, median follow-up 14 months (range 3–22) | Cattanach et al (1989)69 | |
| STIs | ||||
| Mooncup (vaginal) | Study end survey: menstrual cup six (4%) of 144, pads nine (5%) of 202, and usual practices (control) 12 (8%) of 156; cup vs control p=0·11, and cup vs pads p=0·87; when follow-up was ≥9 months: cup four (40%) of 101, pads seven (5%) of 143, and usual practice 11 (11%) of 104; cup vs control p=0·004, and cup vs pads p=0·60 | Presence of either C trachomatis, T vaginalis or N gonorrhoea; cluster randomised trial of schools in Kenya; median follow-up 11 months (range 3–15)* | Phillips-Howard et al (2016)5 | |
| Reproductive tract infections | ||||
| Mooncup (vaginal) | Study end survey: cup 31 (22%) of 144, pads 58 (29%) of 202, and usual practice (control) 42 (27%) of 156; cup vs control p=0·36, and cup vs pads p=0·19 | Presence of either B vaginosis or C albicans; cluster randomised trial of schools in Kenya; median follow-up 11 months (range 3–15) | Phillips-Howard et al (2016)5 | |
| Other adverse events | ||||
| Urinary incontinence | ||||
| Femcap (first model of femmycycle, vaginal) | FDA database: one case report; event July, 2014; pelvic pain and urinary incontinence when wearing and removing menstrual cup; urine sample negative for infection | Self-report; stopped using menstrual cup | FDA database14 | |
| Displacement of IUD when using menstrual cup | ||||
| NR | IUD expulsion 6–8 weeks after insertion: menstrual cup five (4%) of 135, tampon 11 (2%) of 469, pads: seven (4%) of 169; cup vs tampon p=0·57, and cup vs pads: p=0·92 | Retrospective cohort; expulsion of an IUD occurs in approximately one in 20 women and is most common in the first 3 months after insertion; expulsion commonly occurs during menstruation; some recommend not to use internal sanitary protection for 3–6 weeks after insertion because of an increased infection risk | Wiebe et al (2012)57 | |
| Mooncup (vaginal) | FDA database: one case report; event July, 2012; potential IUD dislodgment after Mooncup removal; patient had an ectopic pregnancy and needed surgery | Patient felt pain after removal of Mooncup and had the position of the IUD checked at a health centre where it was declared in position; 2 months later she was found to be pregnant | FDA database14 | |
| NR | Case series of seven women with IUD expulsion when removing menstrual cup; expulsion occurred 1 week to 13 months after insertion of IUD and was recurrent in two women; of seven women, two choose to use different contraception; the five others had their IUD re-inserted | Two women opted for cutting the wires of the IUD close to the cervix to avoid the problem; authors also stress importance of releasing vacuum of menstrual cup before removal | Seale et al (2019)64 | |
| Endometriosis because of menstrual backflow via use of menstrual cup | ||||
| Tassette (vaginal) | Position of cup confirmed with X-ray imaging | “Hence the free space available in the upper vagina plus the capacity of the cup itself are ample to accommodate several times the amount of blood passed in a complete menstrual cycle” | Pena et al (1962)52 | |
| Tassette (vaginal) | No evidence for backflow | “Thin watery solutions could not be introduced under high pressures during the menstrual flow in 6 multiparous women” | Karnaky et al (1962)70 | |
| Keeper (vaginal) | Case report: dysmenorrhoea 2 years after start of menstrual cup use (10 years ago tubal ligation); laparoscopy showed adenomyosis and endometriosis, treated with laser; patient stopped use of menstrual cup; pain decreased after surgery; 2 years of follow-up | “The observations in our patient suggest that it may be useful to inquire about use of these devices in women with pelvic pain or endometriosis”; petition for revoking of market approval to US FDA rejected because of lack of evidence74 | Spechler et al (2003)68 | |
| Hydronephrosis (ie, renal colic) | ||||
| NR | Case report: severe colicky flank pain; CT scan showed menstrual cup was slightly dislocated, pressing into left ureter | “The extraction of the menstrual cup resulted in resolution of hydronephrosis and associated symptoms” | Adedokun et al (2017)60 | |
| NR | Case report: 3 h of back pain on the right side; low-dose unenhanced CT scan showed entrapment of left vaginal wall and part of interolateral bladder wall; improperly positioned menstrual cup | Symptoms and swelling disappeared after removal of menstrual cup, confirmed by another CT scan; patient had used a menstrual cup for a long time with no previous problems, and continued use of cup; no problems at follow-up after several weeks | Stolz et al (2019)62 | |
| NR | Case report: 3 h of pain in the right flank, and nausea during menstruation; X-ray imaging showed menstrual cup orientated to the right | “The symptoms and the ureterohydronephrosis relieved completely after the removal of the device”; patient had used a menstrual cup for 2 years | Nunes-Carneiro et al (2018)61 | |
Entries in FDA database14 for softcup not entered if before 2011, to avoid double reporting with North et al (2011).13 NR=not reported. NA=not applicable. TSST-1=toxic shock syndrome toxin-1. TSS=toxic shock syndrome. FDA=US Food and Drug Administration. IUD=intrauterine device. UTI=urinary tract infection. STI=sexually transmitted infection.
*
The decrease in STIs in the trial in Kenya in the groups in which either menstrual cups or sanitary pads were provided is thought to be an indirect effect because of the decrease in risky sexual behaviour to obtain money to buy pads.