Studies have shown the risk of developing breast cancer is related to a woman’s exposure to chemicals, xenoestrogens (estrogen mimickers), estrogen, and the hormones produced by her ovaries.

Pregnancies reduce the number of menstrual cycles, thereby reducing a woman’s exposure to ovarian hormones.

While women in today’s society have fewer children at later ages, let’s take a closer look at reproduction information regarding breast cancer and prevention.

Pregnancy Factors Lowering the Risk of Breast Cancer

A woman with multiple, full-term births in her twenties has a reduced risk of breast cancer.

• During full-term pregnancy, breast cells mature. Mature breast cells are more resilient against mutation than immature cells. Hence, full-term pregnancies add protection against cancer.
• Women birthing five or more children may have a 50% less risk of breast cancer than women with no children.
• Women completing their first full-term pregnancy before age 20 reduce their risk of hormone receptor-positive breast cancer by 50% compared to women whose first full-term pregnancy occurs after 30.
• Women who have had preeclampsia may have a decreased risk of developing breast cancer.

Pregnancy Factors Increasing the Risk of Breast Cancer

 The older a woman is at her first full-term pregnancy, the higher her risk of breast cancer.

• During pregnancy, breast cells grow rapidly. Genetic damage in the breast cells copies as the cells multiply. Damage may lead to breast cancer, and the likelihood increases with a woman’s age.
• Women older than 30 who give birth have a higher risk of breast cancer than women who never give birth.
• Recent childbirth increases the short-term risk of breast cancer—the risk of cancer declines after ten years.
• The use of diethylstilbestrol (DES) during pregnancy may have a slightly higher risk of developing breast cancer. DES, a synthetic estrogen, was used between 1940 and 1972 to prevent miscarriages.
• Daughters of women who took DES during pregnancy may also have a slightly higher risk of developing breast cancer after 40.

Premature Deliveries and Breast Cancer

 Abortions or miscarriages may increase the risk of breast cancer.

• During the first two trimesters, high estrogen levels stimulate cellular division in the breasts and increase the number of immature breast cells.
• Breast cells only mature during the third trimester.
• Some studies suggest that premature deliveries before 32 weeks may double the risk of breast cancer.
• One study suggests a teenage pregnancy terminated between weeks 9 and 24 increases breast cancer risk by 30%.

Reducing the Risk of Breast Cancer Based on Reproductive History

Along with considering a healthy lifestyle and this reproductive information, women can consider reducing estrogenic exposure and consulting with functional health professionals to test and address estrogen metabolism and balance issues in the body.