By tf-lawyer.com According to statistics, the average age for girls born in the United States between 2000 and 2005 to start menstruating is 12 years old. Over the past two decades, the rate of breast cancer among women under 50 has increased by at least 15%. The most common type of breast cancer is estrogen receptor-positive breast cancer (ER+), which means that the cancer cells respond to estrogen, resulting in tumors influenced by this hormone.
NBC News reports that the rise in ER+ breast cancer is largely driving the increase among young women. Some doctors suspect that this trend may be related to the earlier onset of menstruation and delayed childbirth among women in the U.S.
Dr. Alexandra Thomas, an oncologist at Duke Health, stated, “Women are exposed to many forms of estrogen throughout their lives, which could be a major factor, but we don’t know why we’re seeing these changes happening earlier.”
Researchers suggest that several factors could contribute to this situation, including obesity, alcohol consumption, genetics, and hormonal contraceptive methods. However, the role of earlier puberty in increasing breast cancer risk is garnering more attention.
For decades, the age of onset of puberty in young girls has been declining, especially among African American and Asian American populations. Dr. Adetunji Toriola from the Siteman Cancer Center at Washington University said, “This work is still in its early stages, but we have found from previous studies that certain reproductive factors may be linked to a higher risk of breast cancer.”
A study published in March in JAMA Network Open indicated that women born between 1950 and 1969 had an average menarche age of 12.5, with fewer than 9% starting menstruation before age 11—considered too early. Meanwhile, only 0.6% had their first period before age 9. In contrast, girls born between 2000 and 2005 have a lower average age of menarche at 12 years—40 to 50 years earlier than their aunts, who averaged 12.5 years. There has also been a 15.5% increase in early onset and a 1.4% rise in those starting their periods too early.
Eleonora Teplinsky, the head of women’s oncology at Valley Health System in New Jersey, commented, “If menstruation begins before age 11, the risk of developing breast cancer is higher, and the average age for girls beginning menstruation continues to decline.”
Furthermore, women are increasingly having children later in life or choosing not to have children at all. Ann Partridge, co-founder and director of the Program for Young Adults with Breast Cancer at Dana-Farber Cancer Institute, noted that while pregnancy can temporarily elevate a woman’s risk of breast cancer, it slightly lowers long-term risk.
Partridge explained that women experience amenorrhea during pregnancy, but, “This is not related to estrogen. Instead, changes in the breasts after childbirth may increase the breast cancer risk for women who give birth later.”
