According to a report by
The Sun UK, a mother who suffered persistent bloating for three years discovered she actually had two surgical sponges left inside her for up to nine years.
The 42-year-old had undergone two c-sections, one six years ago and one nine years ago.
When doctors examined her after she complained of bloating they found two masses near her hip bones.
A CT scan revealed two "hyperdense, stringy" masses, according to the New England Journal of Medicine case report.
The woman needed surgery to remove the masses which turned out to be surgical sponges covered in "thick, fibrous walls" from their time inside her abdomen.
The sponges were left behind during her c-sections, but it is not clear which one.
Dr Takeshi Kondo, from Chiba University Hospital in Japan where the woman was treated, said he believed the sponges came from the same surgery.
During a c-section doctors often use sponges in the spaces between the colon and abdominal wall, to stop the intestines getting in the way, Dr Kondo told Live Science.
Leaving surgical sponges or other instruments inside a patient's body during a procedure is considered a "never event", meaning it should never happen.
But some gynaecological surgeries come with a greater risk of these events occurring.