Breast ironing is a practice of flattening a girl’s breast with hot objects. In this image, a woman breastfeeds her 13-week son in Dublin, Ireland, May 26, 2018. PAUL FAITH/AFP/Getty Images

The United Kingdom National Education Union wants breast ironing awareness to be a part of school curriculum in order to protect girls from abuse.

Breast ironing is a practice of flattening a girl’s breast with hot objects including stones and hammers for a period of time in order to delay breast formation. Several pre-teen girls across the U.K. were reportedly subjected to the practice.

BBC reported a woman stating that she was subjected to the practice at the age of 10. Her mother, who descends from West Africa, told her that, "if I don't iron them, men will start coming to you, to have sex with you.”

"Time does not erase that kind of pain. You're not even allowed to cry out. If you do, you [are said to] have brought shame to your family, you are not a 'strong girl,’” she explained.

The woman added that she moved away from the family after her mother proposed to get her eldest daughter’s breast ironed.

Another woman told the BBC's "Victoria Derbyshire" that she was subjected to the practice for several months at the age of 13.

"According to her, maybe I was attractive because of my breasts, so if she can iron them and I'm flat, then maybe I'll be ugly and no-one will admire me,” she said, adding that damage became apparent when she started breastfeeding her baby a few years later.

The United Nations described the practice as one of the five most under-reported gender-based crimes in the world. The practice was usually carried out by family members in order to “protect” the girls from crimes such as rape.

Leethen Bartholomew, head of National FGM Center, said, "In practicing communities, it is believed many boys and men believe girls whose breasts have grown are ready to have sex. Therefore elders – mothers, grandmothers, aunties, etc. – believe that by suppressing a girl’s development of her breasts she will be protected,” the Refinery 29 reported.

The practice can cause severe health issues, depending on the type of object used. This includes dissymmetry of the breasts, cysts, infection and in some cases complete disappearance of the breasts.

Describing breast ironing as a “sensitive and hidden crime,” Angie Marriott, a former gynecological nurse said, "I know this is happening because people have divulged it to me. And they've said it's the first time openly that they've ever spoken about what's happened to them, and they felt ashamed."