Use period cups properly ‘to avoid complications’ – experts
Menstrual cups have been billed as sustainable alternatives to single-use period products.
![Hand holding two menstrual cups](https://www.expressandstar.com/resizer/v2/https%3A%2F%2Fcontentstore.nationalworld.com%2Fimages%2Fb7b269c3-94e6-45c6-826a-d796a77e29b3.jpg?auth=ba8ee6e61df814783c1850b520853e01c71501128802d8dec11dcb642b48c2fb&width=300)
Women have been urged to make sure they position period cups correctly after medics reported a rare case where use of a menstrual cup was linked to kidney problems.
Menstrual cups are an alternative to pads and tampons.
They are made from silicone and work by collecting blood, rather than absorbing it like other period products.
Unlike single-use items, they are washed and can be used again.
![menstrual cups next to a pad and a tampon](http://content.assets.pressassociation.io/2025/02/10094354/5dea0305-8f01-4eaa-9e90-e702595d1497.jpg)
The products have grown in popularity in recent years, but users are now being urged to make sure they are choosing the correct cup size and know how to insert the cups properly.
It comes after medics documented rare complications linked to a cup in BMJ Case Reports.
Experts from Denmark highlighted how lopsided placement blocked urine flow into the bladder of a woman in her 30s.
The woman sought medical care due to intermittent pain in her side and blood in her urine.
Scans revealed a swollen right kidney and ureter — the tube that carries urine away from the kidneys.
The scans also showed that her menstrual cup was placed in the right side of her vagina, next to the opening of the ureter into the bladder.
As a result they asked the woman not to use the cup and return for tests a month later.
The second round of tests revealed that the swelling had gone down and that her urine function was normal.
Medics said that the positioning of the cup had obstructed the flow of urine from the right ureter.
The woman was diagnosed with ureterohydronephrosis – the swelling of one or both kidneys which occurs when the body does not fully empty urine.
The physicians said that the complication was “rare” but urged women and doctors to be aware of the possible side effects.
“Complications of menstrual cup usage are probably few, but poorly described,” they wrote.
“A few cases of more serious complications including effects on the upper urinary tract have been reported, including the present case.
“The increasing use of menstrual cups calls for more knowledge on complication rates to enlighten both users and clinicians.
“Users of menstrual cups should be made aware of symptoms that call for medical evaluation and receive the necessary information to be able to choose the correct cup size, material, shape, and insertion method.
“Clinicians ought to include it in their differential diagnoses in women with menstrual cups.”