As a girl enters her puberty, she witnesses a number of physical changes. An unusual increase in the size of boobs is one of the most prominent signs of puberty. But this is not the only stage where you experience an increase in breast’s size. This change of size is a life-long process. In some, it is more evident than the others. And those women’s minds are often occupied with the thought, ‘why are my breasts bigger’. Let’s try to find out the answer.

Common Causes of Bigger Breasts

A prominent change in a female’s breast’s size starts between the age of 8 to 13. The very first change is the appearance of small bumps or buds on the flat chest. The normal growth of boobs continues (sometimes one breast grows faster than the other) till a girl reaches her teenage or early twenties. It’s the stage of 20’s, when she gets into her normal size. But the growth doesn’t stop here. Here are the most common reasons behind a change in your breast’s size (bigger).

Hormonal Changes

Hormonal fluctuations are the most common cause of change in women’s breast’s size. Puberty is a stage when our body witness maximum hormonal surge. Especially estrogen, a female sex hormone, causes a lot of noticeable changes in the tissue growth of the breasts. The alterations of breast’s size do not appear within days. But it takes several years to get a fuller form.


The Luteal Phase of Menstruation

Within the initial years of the breast’s growth, girls experience their first menstrual cycle. Menstruation cycle is divided in two phases; follicular phase and Luteal phase. If you ever feel like why are my breasts bigger during menstruation, that’s because of Luteal phase. This phase starts after the ovulation. And right after ovulation, your body experiences a surge in progesterone and estrogen level that causes maximum blood flow towards your breasts. As a result, you feel firmer and fuller breasts.


Weight Gain

A normal weight gain by a woman would surely affect her breasts growth. Breasts consist of fatty tissues and are more prone to gaining weight. So, as she gains weight, she witnesses bigger breasts and vice versa.



When you are having sex, you are quite likely to feel a change in your breasts size. Foreplay is the time when a woman faces an increase in her heart rate and blood pressure. As a result, she ends up with erected nipples and fuller breasts.



As a woman gets pregnant, her body starts preparing her breasts for breastfeeding. This is the stage when most of the women experience a heaviness in breasts along with an increase in the cup size.



Right after delivering the baby, your body starts producing milk. As long as a woman is breastfeeding, she will observe breasts, bigger than the pre-pregnancy size.



Your bigger breast can also be the outcome of your genes.

Other Reasons of Breast’s Growth

There are some abnormal reasons of why you have bigger boobs. Let’s read on to discover them.

1. Use of Birth Control Pills

Using contraceptives is quite common. But most of the women using it, have no idea of the presence of estrogen in it. The more you use them, the more you are likely to think, why are my breasts bigger. So, if you are uncomfortable with bigger breasts, look for some other way of birth control or pills with less quantity of estrogen.

2. Medication

There are certain anti-depression and anti-psychotic medications (Risperidal particularly) that are known to increase the pro-lectin levels in you. As a result, you may face an abnormal growth of breasts, leakage of milk from breasts (even without being pregnant), or pain in breasts before menstruation. In case you have any of these symptoms, consult your doctor. If pain around breasts intensifies, using ibuprofen may help.

3. Breast Cancer

If you notice any of the symptoms like a sudden increase in breast’s size, abnormal lumps, inflammation, redness or tenderness of breasts, it might be breast cancer. Numerous environmental, social, or nutritional factors can be counted as the reason of breast cancer. Learning more about those factors can help prevent the risk.

4. Benign Tumors

These are non-cancerous tumors that may cause enlargement of breasts as a whole or in a specific area, in the form of swelling.

5. Fibrocystic Breasts

This medical condition may lead you to the growth of abnormal lumps in breasts.

6. Mastitis

It’s a very common symptom among breastfeeding moms. The breasts are enlarged with intense swelling, pain and infection.

What to Do?

If you find any of the above-mentioned symptoms of abnormal growth of breasts, don’t waste your time in thinking, ‘why are my breasts bigger’. All of these are curable conditions. Consult your physician for an expert advice and get it cured as soon as possible.

How Breast Changes in Different Ages

Change in structure and tissues of breasts continue in different ages. Let’s see how age affects the growth of breasts.

  • Breast’s size in 20’s

Adolescence is a stage when you experience a change in normal body weight. Losing or gaining of body weight directly affects the breast’s size. It’s a stage where you have firmer breasts with more fibrous tissues. Many women get pregnant in their 20’s, followed by the whole process of breastfeeding. That also brings an evident change in breast’s size.

Note: To have very small lumps or bumps in breast is a normal thing in your 20’s, unless you find the one that grows abnormally.

  • Breast’s Size in 30’s

By the time you enter in your 30’s, the breasts tend to grow in size, leaving many in surprise saying, why are my breasts bigger? Some women experience increase in size up to 3 cups.

  • Breast’s Size in 40’s

In this stage, the breast’s skin loses its elasticity. Women experience a reduction in the production of estrogen. And the tissues in breasts are replaced by fats. Fat lacks firmness, so you have breasts with nipples pointing downwards. In other words, you end up with breasts ptosis. All that a woman can do in this stage, is to wear a push-up bra.

  • Breast’s size in 50’s

It’s the menopause stage (no production of estrogen), so you are going to have droopier breasts with saggy skin.

Note: Many figure-conscious women opt for artificial stimulation of cells with hormone therapy, in this menopause stage.

  • Breasts Size after 50’s

By this time, your breasts have a wider space between them. Breasts shrink, sag and lose its density.


Please Log In or add your name and email to post the comment.