Because breast cancer is a hormone-sensitive cancer that involves an imbalance of the female sex hormones estrogen and progesterone, it may affect your period, too. These hormones affect breast growth and development and menstruation.
Many people who receive a breast cancer diagnosis don’t have any symptoms.
But because breast cancer is a hormone-sensitive cancer, it may sometimes affect your period. Irregular periods may also be a sign of a different underlying health condition.
Symptom vs. risk factorIrregular periods are not a direct symptom of breast cancer. They may be considered risk factors, which raise your risk of developing the disease, but don’t guarantee it.
In a 2020 review of older studies, researchers found that longer cycles (more than 33 days) may be associated with a decreased risk of breast cancer.
On the other hand, shorter cycles (fewer than 26 days) and a higher frequency of periods may be associated with an increased risk of breast cancer.
However, more current research is lacking, and one study in the review suggests the opposite — that longer cycles are associated with an increased risk and shorter cycles are associated with a decreased risk.
Other studies in the review found that neither longer nor shorter cycles had an effect on breast cancer risk.
Research has linked increased levels of estrogen and progesterone to a higher risk of breast cancer.
Both are female sex hormones, but males also have small amounts. This makes it possible for males to also develop breast cancer, though the rate is low.
Estrogen and progesterone are products of your ovaries. Estrogen is involved in breast tissue growth and development. Progesterone is related to menstrual cycle regulation and breast development.
An imbalance of either of these hormones can activate estrogen or progesterone receptors, which may then impair or excessively signal cell growth and division in the breasts.
This is what may lead to the formation of breast tumors.
However, defining the threshold for a “hormone imbalance” is difficult, as every individual’s levels vary.
How are these hormones related to your period?
While estrogen peaks right before ovulation, a consistently higher level may cause light or heavier bleeding during your period.
Progesterone peaks during pregnancy (it helps prepare your body for a baby) and during the luteal phase. But consistently high levels may delay ovulation, potentially leading to irregular cycles and lighter bleeding during your period.
While irregular periods may or may not be a sign of breast cancer, if you get treated for it, the treatment method you and your doctor discuss may impact your periods.
Chemotherapy is known to
Other breast cancer treatments that may affect menstruation are hormone therapy and radiation, especially if you have radiation to the pelvic area.
Generally, early age at menopause may be “
The same goes for procedures to remove the ovaries, which may result in surgical menopause, and the breasts.
These surgeries are considered protective because, without your breasts, you’ll be less likely to develop a breast tumor. Without your ovaries, you’ll stop producing estrogen and won’t menstruate.
Though the risk of breast cancer decreases following these operations, they’re typically reserved for those at very high risk.
Breast cancer may or may not be the cause of irregular periods. Other health conditions that may affect your periods include:
Taking hormonal birth control or having an intrauterine device (IUD) implanted may also change your bleeding pattern during your period.
You should speak with your doctor if your period is irregular with no known cause or if you have concerns about your menstrual cycle.
You should also immediately speak with your doctor if you show any other signs of breast cancer.
Early detection can help improve treatment outcomes. You should continue getting regular breast cancer screenings and performing breast self-exams.
Breast cancer is a hormone-sensitive cancer, so high levels of the female sex hormones estrogen and progesterone may increase your risk.
These hormones are involved in breast tissue growth and development and play a part in your menstrual cycle.
A higher frequency of menstruation (shorter cycles) may be associated with a higher risk of breast cancer, but the research is conflicting.
Speak with your doctor if you have concerns about your menstrual cycle and if you’re experiencing other symptoms of breast cancer.