Early Menarche (Periods) and Breast Cancer Risk

Menarche is the first occurrence of menstruation (when a person assigned female at birth has her first period). Researchers know that age, genetic changes, family history, and smoking are some of the risk factors for breast cancer. Early menstruation is now a part of the discussion. 

This article reviews early menstruation, the age of menarche as a risk factor, known breast cancer risk factors, and lowering risk through early detection.

What’s Considered Early Menstruation?

Menarche is the first occurrence of menstruation (a menstrual cycle or period) and starts during puberty, typically around age 12, but can vary by several years.

Puberty is when a girl's body starts producing the hormones responsible for ovulation and regular menstruation. Early menarche is when menstruation occurs before the age of 12. 

Multiple factors can lead to early menarche, including:

• Increased subcutaneous fat (fat in the innermost layer of skin)
• High body mass index (BMI) (25 or higher)
• Consuming high concentrations of fructose (the sugar present in sweetened beverages like soda)
• Geographic location 
• Ethnicity 
• Socioeconomic status
• Poverty level 
• Family structure
• Living arrangements 
• Nutrition

Most girls will not have regular menstrual cycles (periods) at menarche. However, the age of their first period defines menarche regardless of when they have their next menstrual period. A short time between menarche and regular menstrual cycles is another risk factor for breast cancer. 

Late Menstruation 

Delayed or late puberty occurs when females do not develop breasts by age 13 or have their first menstrual period by age 16. Most of the time, menarche progresses normally once they do reach puberty. 

The most common cause of late puberty is a pattern in the family. It can also be due to the following:

• Lack of body fat
• Extreme, frequent physical activity (swimmers, runners, dancers)
• Eating disorders
• Being undernourished
• Medical conditions 
• Endocrine (hormone) conditions, such as growth hormone deficiency 
• Genetic factors, such as the hormone disorder Kallmann syndrome 
• Cancer treatment

Breast Changes During Menstruation 

Puberty begins between the ages of 8 and 12 in girls. The body starts to release reproductive hormones such as estrogen and progesterone. During this time, the body experiences multiple changes, and girls begin to develop breasts. Menarche usually occurs about two years after the breasts start to develop.

Once menstruation begins, you may notice that your breasts are tender or sore right before you start your period. This tenderness is due to the changes in hormone levels during this time. It is normal and typically goes away quickly. 

Menarche as a Risk Factor for Breast Cancer

Early menarche is associated with a higher risk of several health issues later in life. These include:

• Obesity
• Diabetes
• High cholesterol
• Depression
• Eating disorders

Current research also shows that early menarche increases the risk of breast cancer. 

Many breast cancers are hormone receptor-positive, meaning the cancer cells are sensitive to hormones such as estrogen and progesterone. One theory suggests that more prolonged exposure to cyclic hormonal stimulation of the breast tissue accounts for the correlation between early menarche and breast cancer. 

One group of researchers found that women with short, numerous menstrual cycles also have a higher risk of breast cancer due to increased cell division during the luteal phase (after ovulation). Data also shows that excessive exposure to exogenous (made outside the body) estrogen and progesterone increases the risk more than estrogen alone.

List of Known Risk Factors 

The following are known risk factors for breast cancer: 

• Older age: Most breast cancers are diagnosed after 50.  
• Genetic mutations: This includes mutations in the BRCA1 and BRCA2 genes and non-BRCA genetic mutations
• Early menarche: Starting your period before you are 12 years old.
• Late menopause: Menopause that occurs after you are 55 years old.
• Dense breasts: Not only do dense breasts increase your risk, but they can also make it harder to see tumors on a mammogram.
• History of breast cancer: Those who have had breast cancer are at a higher risk of getting it again.
• Family history: The risk of breast cancer increases for those with a first-degree relative or multiple relatives with breast or ovarian cancer.
• Previous radiation therapy: Breast cancer risk increases for those who have had radiation treatment to the chest or breasts before age 30. 
• Exposure to diethylstilbestrol (DES): This medication was given to pregnant women in the United States from 1940 to 1971 to prevent miscarriage.
• Lack of exercise: Not being physically active increases breast cancer risk.
• Having excess weight or obesity: This is especially true after menopause.
• Hormones: This might include early oral contraceptive use or hormone replacement therapy (HRT). HRT has estrogen and progesterone taken for menopause symptoms. HRT raises the risk of breast cancer when taken during menopause for more than five years.
• Reproductive history: Risk increases for those who have their first pregnancy over age 30, don’t breastfeed, or never have a full-term pregnancy.
• Alcohol and tobacco: Risk increases for those who drink alcohol excessively and those who smoke.

Lowering Risk Through Early Detection 

Breast cancer is the second most common cancer (after skin cancer) in the United States. Early detection (finding cancer before it causes symptoms) through breast cancer screening increases the chance of survival. The following are breast cancer screening tests: 

• Breast exam: Your healthcare provider performs a breast exam to detect any lumps in the breast.
• Mammogram: This is a radiology test (X-ray) of the breast. It's the most commonly used tool for screening or diagnosis. 
• Breast ultrasound: An ultrasound uses sound waves to examine breast tissue. It is often used after a suspicious finding on the mammogram. However, some providers recommend it as a screening tool for women with dense breasts.

Summary

"Menarche" refers to the first occurrence of menstruation or the age a female has her first period. Early menarche is associated with a higher risk of health conditions, such as obesity, diabetes, and depression. Research now links early menarche as a risk factor for breast cancer. 

Other breast cancer risk factors include age, genetic changes, family history, dense breasts, excessive alcohol, smoking, and more. Breast cancer screenings are essential for early detection and include breast exams, mammograms, and breast ultrasounds. 

A Word From Verywell 

It can be frightening to realize that some of the risk factors for breast cancer, such as the age of menarche, are out of your control. However, you do have control over factors that decrease risk, such as exercising, maintaining a healthy weight, quitting smoking, and reducing alcohol intake. Keeping up with breast cancer screenings can help with early detection and lead to better outcomes.