One breast is suddenly bigger than the other before period

Have you ever looked into the mirror and felt concerned about why one of your breasts is bigger than the other? If yes, you’ve landed at the right place. Breast asymmetry is when one breast differs from the other in terms of size, volume, position or form. And it’s common. A woman’s breasts may fluctuate in size or volume for a variety of reasons including trauma, puberty and hormonal changes. Come let us find out more about unequal breast size.

Dr Tanaya Narendra, popular on social media as Dr Cuterus, gave her Instagram followers a sneak peek into the subject of breast size, which not many women up about.

The expert says that the phenomena is common. For most people, it’s the left breast which is bigger. But if your right breast is bigger, there’s nothing abnormal about it. This difference can be as large as one cup size and there’s nothing to be worried about.

Also read: Adopt these 6 habits for healthy boobs

Some likely causes of unequal breast size are:

1. Normal differences in growth

Most of our body parts are not perfectly symmetrical. This may include our legs, hair and eyebrows. So, the reason for your unequal breasts may be due to typical physiological variances which are beyond one’s control.

2. Period cycle

During each phase of your menstrual cycle, your breast tissue keeps changing. For instance, when you are ovulating, they could seem bigger and more sensitive. When menstruating, they contract.

3. Change in hormones

Even if both the breasts finish developing at the same time, it is quite possible that one breast may begin to develop before the other when hormones shift during puberty. So, it can be due to hormonal changes.

4. Traumatic injury

Breast asymmetry can result from injury to breast tissue before it has fully matured, possibly between the ages of 10 and 11 when adolescent girls go through the phase of puberty. Asymmetric breast growth may result from traumas to the chest such as some big injury, trauma, infection, or radiation.

5. A skeletal issue or some medical problem

One breast grows noticeably bigger than the other in a condition called juvenile or virginal hypertrophy of the breast, which is not that common. This medical problem frequently results in physical and psychological issues and is treated by a surgery.

According to Dr Narendra, a sudden change in the size of your breasts should raise an alarm, and you must visit a doctor in that case.

Check out her full video here!

Is breast asymmetry a symptom of breast cancer?

Breasts that are uneven are typically nothing to worry about. Regular scans are necessary to ensure that any breast abnormalities are found early, though. However, if the density of your breasts suddenly changes or if the asymmetry of your breasts varies very frequently, this could be a sign of breast cancer.

According to a 2015 research, women who have a breast asymmetry ratio of over 20 percent may be more likely to get breast cancer.

American College of Obstetricians and Gynecologists website. Dysmenorrhea: painful periods.www.acog.org/patient-resources/faqs/gynecologic-problems/dysmenorrhea-painful-periods. Updated January 2022. Accessed August 12, 2022.

Expert Panel on Breast Imaging; Jokich PM, Bailey L, et al. ACR appropriateness criteria breast pain. J Am Coll Radiol. 2017;14(5S):S25-S33. PMID: 28473081pubmed.ncbi.nlm.nih.gov/28473081/.

Mendiratta V, Lentz GM. Primary and secondary dysmenorrhea, premenstrual syndrome, and premenstrual dysphoric disorder: etiology, diagnosis, management. In: Gershenson DM, Lentz GM, Valea FA, Lobo RA, eds. Comprehensive Gynecology. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 35.

Sandadi S, Rock DT, Orr JW, Valea FA. Breast diseases: detection, management, and surveillance of breast disease. In: Gershenson DM, Lentz GM, Valea FA, Lobo RA, eds. Comprehensive Gynecology. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 15.

Sasaki J, Gelezke A, Kass RB, Klimberg VS, Copeland EM, Bland KI. Etiology and management of benign breast disease. In: Bland KI, Copeland EM, Klimberg VS, Gradishar WJ, eds. The Breast: Comprehensive Management of Benign and Malignant Diseases. 5th ed. Philadelphia, PA: Elsevier; 2018:chap 5.

Last reviewed on: 4/19/2022

Reviewed by: John D. Jacobson, MD, Department of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

If your tire goes flat, a warning sign may appear on the dashboard. If your smartphone battery is low, it may send you an alert. The human body has a similar alarm system. From hives and rashes to pains, fever and vomiting, your body has its own way of letting you know something’s wrong. Some signs are more subtle than others. Breast cancer is one disease that often causes a variety of more obvious signs and symptoms of breast cancer that may alert you to a potential concern to share with your doctor. Since early detection is key, doctors recommend that women know what these symptoms are, and learn how to spot them.

Early signs and symptoms

A new lump in the breast or underarm is one such sign. “In general, if a woman is premenopausal and has a lump that persists without change across different phases of a second or third menstrual cycle, this area must be evaluated,” says Dr. John McKnight, Medical Oncologist at the Breast Center for Advanced Oncology at our hospital near Atlanta. “There are many changes in breast tissue during the normal course of a monthly cycle— some tissue may be enflamed, and cysts may appear. But if a lump appears and stays, then a physician should evaluate it. For postmenopausal women, any lump should be evaluated.”

Women should also be aware if their breasts become asymmetrical­­­­­—meaning one breast appears firmer or larger than the other. “It could mean a mass is pulling the breast to the chest wall,” says Dr. Haritha Pabbathi, Medical Oncologist who treats patients at the Breast Center for Advanced Oncology at our hospital near Atlanta. “This needs to be checked out by an OB-GYN or a primary care physician.”

Breast cancer may also change the appearance of the nipple. “If your nipple usually appears normal and begins to look inverted, that’s a concern,” says Dr. Pabbathi. “There could be a lump pulling your nipple inward.” Cancer may affect the nipple in other ways, too. “If you’re not lactating, there should be nothing flowing from the nipple,” says Dr. McKnight. “Any discharge, especially blood, needs to be checked out. It may be inflammation or an infection, but it should be seen by a doctor.” 

Skin changes, especially redness or inflammation in the breast’s skin, may be indicative of a less common type breast cancer, called inflammatory breast cancer. In some cases, the skin may have ridges or appear pitted, like the skin of an orange. “Just as the skin of an orange has little holes, the breast skin has little holes, too,” says Dr. Pabbathi. “This may indicate a type of breast cancer where there is no lump.”

Talk to your doctor

When breast cancer spreads to lymph nodes under the arm or around the collar bone, a lump or swelling often develops in the area. Dr. Pabbathi says women should pay special attention to these changes. “It may mean the cancer has spread,” she says. “This should also be checked by a health care provider.” Other possible signs include general pain in any part of the breast, irritated or itchy breasts, changes in sensation (feeling tender or warm) and peeling of the nipple skin.

Of course, any of these symptoms may be the result of conditions other than breast cancer, and not every breast cancer causes noticeable signs and symptoms. That’s why it’s important to discuss obvious changes in your breast health with your doctor, and make regular screenings and doctor visits a priority.

Breast health starts with knowing how your breasts normally look and feel. “I try to emphasize to patients that they should be very familiar with their own breast tissue,” says Dr. McKnight. “As a doctor, it’s always better to have a patient be aware of her body and know when something feels unusual. That’s why we advise all women to do breast self-exams. If you feel something unusual, you should have it examined by a physician.”

When breast cancer is caught early, more options may be available to treat it. But being aware of your body and doing regular self-exams is only part of prevention and early detection. Regular mammograms and other screening tests are essential to detecting breast cancer, especially in its early stages, even before symptoms appear.

“We want to find breast cancer before there are any signs,” says Dr. McKnight. “We want to diagnose the disease before it has significant opportunity to spread.”

Can hormones cause one breast to be bigger?

What causes one of your breast to be bigger than the other?

Why is one breast suddenly smaller than the other?