After toxic shock, a new concern is emerging about menstrual protection: when poorly positioned, the cup, a sustainable alternative to tampons, can cause kidney problems. A team of Danish doctors reports the case of a young woman in her thirties for whom the menstrual cup blocked the flow of urine into the bladder. This is called ureterohydronephrosis.
After stopping its use, the symptoms disappeared. These complications are very rare,” "emphasizes Clara Maarup Prip, co-author of the report, Science and Future. The team is indeed referring to five known similar cases. According to the doctor, it is also possible that the number of cases is underestimated: " There is no official count and studies on menstrual cup complications are sorely lacking, making it difficult to draw definitive conclusions," she adds. Their report was published in the journal BMJ Case Report.
Ureterohydronephrosis is caused by a buildup of urine
A woman in her thirties presented to Aarhus University Hospital in Denmark. She complained of intermittent pain in her right flank and blood in her urine. Examination showed swelling of the right kidney and ureter, the tube that drains urine from the kidneys. This was called ureterohydronephrosis. This condition is characterized by swelling of one or both kidneys and the associated ureter due to a buildup of urine,” says Clara Maarup Prip. It can occur for various reasons: stones, tumors, benign prostatic hyperplasia… But on the image, there are no kidney stones.
Read alsoTampons and cups: advice for women and manufacturers against toxic shock
However, the doctors noticed the presence of a menstrual cup right next to the opening of the ureter into the bladder. They then suggested that the young woman stop using it and have a new examination a month later. As hoped, the symptoms then disappeared: the kidney and ureter had deflated and urine flowed normally from both kidneys.The cup had obstructed the flow of urine from the right ureter," conclude the authors.
Three-dimensional reconstruction showing the dilated upper urinary tract and where the ureter is compressed by the menstrual cup. Credit: Dr Gratien Andersen.
Other similar cases
Five very similar cases have been reported. Sometimes, women have reused the menstrual cup without the symptoms reappearing, changing the size of the cup for example. According to the authors, the mechanical stress exerted on the ureter is due to poor positioning of the protection. "When the terminal part of the ureters reaches the bladder, they are close to the vagina, which can affect urinary drainage from the ureter. Correct positioning, as well as the choice of the shape and size of menstrual cups are important to avoid negative effects on the upper urinary tract.", they support. “Currently, menstrual cups can be purchased and used without clinical advice from a healthcare professional, which highlights the importance of detailed and clear information for patients.”
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