Menstrual Cups – How Safe are They?

There’s a lot of information on the internet about menstrual cups and what women think about them. This is great for background information but when you want to find out how safe they are, where do you turn?

Listening to a few women explain that they never had any problems with menstrual cups is good for the soul but it doesn’t really satisfy the logical side of the brain that is looking for details such as:

  • Were there any safety studies done on menstrual cups?
  • If there were studies, how many women were in the study(ies)?
  • What types of infectious organisms were looked for in the studies?
  • Are the menstrual cups safe from causing toxic shock syndrome (TSS)?
  • Are the menstrual cups safe from sexually-transmitted disorders (STDs)?
  • How do they compare to tampons?
  • What do researchers say about the safety of the menstrual cup in their reports? For example, do they say they are a better choice than sanitary napkins and tampons? And what is their reasoning about it?

When you know the answer to these types of questions, you will feel a lot more secure about the safety – or lack of safety from menstrual cups.

So let’s get right down to it and examine six of the top studies on menstrual cups.

Flex Offers Study #1. Canadian Journal of Infectious Diseases & Medical Microbiology, 2015

In this study, doctors reported a case of toxic shock syndrome that resulted from one woman’s use of the menstrual cup. The woman was 37 years old and ended up with Toxic Shock Syndrome the first time she used the menstrual cup.

Now before you get emotional about this, it’s important to get the details. Save your emotions for after you get the details – as you will see that the expense of energy from emotions before the details come in can be spared.

The facts are that the doctors reported that this was the very first case of Toxic Shock Syndrome they had ever seen in a woman using the cup for the first time. It’s the year 2015 and the menstrual cup has already been on the market and used abroad for at least a decade. This gives us another clue as to what is happening here – most likely the woman did not use the cup properly. It’s her first time using it and she frankly did it incorrectly.

This brings to mind a human flaw – humans just don’t like to read directions! And even if she did read the directions, she may not have turned to support from other women in the important how-to’s regarding the menstrual cup. We’ll give you tips on preventing infections in our third article in this series.

The doctors stated in their report: “Menstrual cups have been reported to be an acceptable substitute for tampons. These flexible cups have also been reported to provide a sustainable solution to menstrual management, with modest cost savings and no significant health risk.”

No significant health risk. Acceptable substitute for tampons. These are strong words for doctors from the Department of Obstetrics and Gynecology at Western University in London Ontario to say. Chalk up a big win for safety for the menstrual cup with these doctors despite the woman’s lack of hygiene that caused her medical problem.

Study #2. International Journal Surgical Case Reports, 2018.

Portugese doctors were exceptionally concerned about a patient of theirs that was using a menstrual cup and had really bad abdominal pain that wouldn’t go away with pain medication.

Right there with this statement we know the folly of using pain medications for everything. If pain medication doesn’t lessen the pain you are having, someone is going to have to investigate further to see where the pain is coming from.

In this case, the doctors did an abdominal x-ray and found the cause of the pain – the menstrual cup was sitting on top of the ureter. The ureter is the part of the kidney – a tube – that runs down from the kidney to get to the outside of the body where you can urinate.

When they did an ultrasound test, they found a problem from compression of the right ureter and it was backing up the urine in the kidneys. No wonder why she had pain!

Now here’s the really important info: “the symptoms and the ureterohydronephrosis relieved completely after the removal of the device.”

Once the menstrual cup was removed, all the pain was gone because the cup wasn’t sitting on top of the ureter anymore.

The doctors went ahead and stated: “Despite being a safe device, problems with the menstrual cup could occur and we believe that the mechanism behind this clinical picture was the extrinsic compression of the right ureter by the cup… it is important for clinicians to be aware of this device and possible complications associated with its use.”

Once again, we have another woman who did not insert the menstrual cup properly. There should never be pain during the use of the menstrual cup.

Study #3. Lancet Public Health Journal, 2019.

These UK researchers set out to review all the international studies on menstrual cup leakage, acceptability and safety. Regarding safety, they were looking for any problems with vaginal abrasions, any effects on vaginal microflora, any effects on the reproductive, digestive or urinary tract, and safety in poor sanitary conditions.

The researchers found 436 records pertaining to the menstrual cups and determined that 43 studies met their criteria. These 43 studies examined 3319 women using the cups.

Most of the studies reported were on vaginal cups (63%), five were on cervical cups (12%), and the remaining 25% were on mixed types of cups or the type of cup was unknown. Fifteen of the studies were from low or middle income countries.

In all the studies, the researchers commented that the women had to familiarize themselves with the menstrual cup usage over several menstrual cycles. Looking at all the data from 13 studies, 73% of the women wanted to keep using the menstrual cup after the study ended

Four studies showed there were no adverse effects on the vaginal flora (507 women). Out of the 3000+ women, five women had severe pain or vaginal wounds. Six had allergies or rashes. Nine had urinary tract complaints. And five had toxic shock syndrome. The menstrual cup dislodged a previously placed IUD in 13 women, and this happened anywhere from 1 week to 13 months after insertion of the IUD.

In the case of 47 cervical cup users and two vaginal cup users, they had to go to the doctor to get the cup removed.

The researchers’ final conclusion: “Our review indicates that menstrual cups are a safe option for menstruation management and are being used internationally.”

Study #4. British Medical Journal, 2017.

Researchers and doctors from Kenya, the UK, and the U.S. combined their brainpower to see the effects of using the menstrual cup in 30 primary schools in rural western Kenya. They wanted to examine the safety of menstrual cups against sanitary pads in the Kenyan schoolgirls aged 14 to 16 years old.

The researchers tested 604 girls over the course of about 11 months. No cases of Toxic Shock Syndrome were found. The prevalence of Staphylococcus aureus was 10.8% no matter whether or not the menstrual cup was used. Of 65 positives for Staph aureus – the bacteria that causes Toxic shock syndrome – 49 girls were retested.

Ten of them stayed positive but only two tested positive for TSS even though both girls were healthy. They were then given sanitary pads to use instead of the menstrual cups.

This tells us that if TSS is a legitimate concern, the best answer would be to use sanitary pads, not the cups.

Thirty used menstrual cups that were processed in the laboratory found E. coli growth. This was more common in those who were new users of the menstrual cups, not established users. E. coli bacterial contamination comes from improper wiping of the groin area – from back to front instead of from front to back.

The researchers concluded that “no evidence emerged to indicate menstrual cups are hazardous to health or cause health harms among rural Kenyan schoolgirls…”

Study #5. British Medical Journal, 2016.

In this study, doctors and scientists checked to see whether using the menstrual cup had any effect in Kenyan schoolgirls on sexually transmitted diseases. They tested 105 schoolgirls who used either sanitary pads or menstrual cups and found that 7.7% of those who used sanitary pads developed STDs while only 4.2% of those who used the menstrual cup developed STDs.

Reproductive tract infection was 21.5% in menstrual cup users compared to 28.5% of the users of sanitary pads. Of this reproductive tract infection group, 71% of the infections were related to bacterial vaginosis. This is where the flora is imbalanced. Bacterial vaginosis was less prevalent on the menstrual cups (12.9%) compared to 20.3% in the sanitary pads group.

The researchers concluded that provision of menstrual cups and sanitary pads for about one school year was associated with a lower risk of STD and the menstrual cups were associated with a lower bacterial vaginosis risk.

Study #6. Canadian Family Physician, 2011

In a Vancouver Island Women’s Clinic, doctors tested 94 women aged 19 to 40 years old who used either tampons or menstrual cups. They were looking for the women’s satisfaction with the menstrual cups and also discomfort levels, infections, cost and waste.

About 91% of the women in the menstrual cup group continued to use the cup and recommended it to others. The cost of tampons was $37.44 per year compared to the initial cost of a menstrual cup. Vaginal discomfort was initially higher in the menstrual cup group but the discomfort decreased with continued use. There was no difference in symptoms between the two groups. Their concluding comments were that menstrual cups have the potential to be a sustainable solution to menstrual management with moderate cost savings and much-reduced environmental effects compared with tampons.

These studies show an excellent safety record for the menstrual cups.


Can J Infect Dis Med Microbiol. 2015 Jul-Aug;26(4):218-20.

Int J Surg Case Rep. 2018;46:28-30. doi: 10.1016/j.ijscr.2018.04.002. Epub 2018 Apr 9.

Lancet Public Health. 2019 Aug;4(8):e376-e393. doi: 10.1016/S2468-2667(19)30111-2. Epub 2019 Jul 16.

BMJ Open. 2017 May 4;7(4):e015429. doi: 10.1136/bmjopen-2016-015429.

BMJ Open. 2016 Nov 23;6(11):e013229. doi: 10.1136/bmjopen-2016-013229.

Reprod Health. 2018 Aug 17;15(1):139. doi: 10.1186/s12978-018-0582-8.

Can Fam Physician. 2011 Jun;57(6):e208-15.






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