Phthalates are a family of chemicals used to soften plastics and make them more flexible. They are added to thousands of everyday products from nail polish, perfumes, fast food wrappers, shampoo and soaps to piping, tubing, construction materials, electrical wiring.
A new study from Northwestern University finds phthalates can stimulate a series of reactions in the body that lead to the growth of uterine fibroids.
Fibroids are tumors made up of smooth muscle cells and fibrous connective tissue that develop in the uterus. It’s estimated that 70 to 80 percent of women will develop fibroids in their lifetime, but not everyone will develop symptoms or require treatment. It’s extremely rare for a fibroid to go through changes that transform it into a malignant tumor. However, women who have rapid growth of uterine fibroids or fibroids that grow during menopause should be evaluated by their healthcare provider.
Although fibroids are usually not cancerous, they can cause difficulties. One quarter of women with fibroids may experience heavy menstrual bleeding, pelvic or leg pains, anemia, miscarriages, infertility, as well as large abdominal tumors that can make surgical procedures more difficult.
Women who experience a high exposure to particular phthalates such as DEHP — found in shower curtains, car upholstery, shoes and other products — are at higher risk for experiencing troubling symptoms with their fibroids.
Fibroids sometimes occur singly, or a woman may have multiple uterine fibroids. If symptoms cause problems they can be treated with medication or surgery. When symptoms are severe or the fibroids are large, a hysterectomy — the surgical removal of the uterus — may be recommended.
The Northwestern researchers found that women who experience a high exposure to particular phthalates such as DEHP — found in shower curtains, car upholstery, shoes and other products — are at a higher risk for experiencing troubling symptoms with their fibroids.
Although studies in the past have indicated an association between uterine fibroid growth and phthalates, the new research, which took uterine cells from women undergoing hysterectomy or myomectomy (surgical removal of fibroids), went a step further. It discovered that exposure to DEHP triggers a particular hormonal pathway that activates a responsive receptor called AHR to bind to DNA — causing the increased growth of fibroids.
“If there’s tumor, phthalates make the tumor bigger,” said corresponding study author, Serdar Bulun, chair of the department of obstetrics and gynecology at Northwestern University’s Feinberg School of Medicine and a Northwestern physician, in a press release.
The study’s researchers hope their findings will lead to new strategies to prevent and treat uterine tumors that cause difficult symptoms. “We are thinking about developing drugs to target this pathway. But drug development is a tedious and slow process,” Bulun said.
In addition to exposure to phthalates, there are several other risk factors that can increase the chances of developing uterine fibroids. They include:
- Age (older women are at higher risk than younger women)
- African American race
- Family history of uterine fibroids
- High blood pressure
- No history of pregnancy
- Vitamin D deficiency
- Food additive consumption
- Use of soybean milk
The study is published in Proceedings of the National Academy of Sciences.