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Your breasts develop throughout most of your life and as you go through puberty, the menstrual cycle, pregnancy, and menopause. Some breast growth, however, may be a sign of infection or breast cancer.

Normal breast development happens throughout the majority of a woman’s life. It begins before you’re born, ends at menopause, and has several stages in between. Because the stages coincide with a woman’s phases of life, the exact timing of each stage will be different for each woman. These stages will be different as well for those undergoing gender transition. The size of the breasts will also vary a lot from one person to another.

In any case, it’s important to be aware of normal development so that you can spot any potential issues early.

It’s common to have questions about your breasts in different development stages, especially since every woman’s breasts are different. Let’s look at a few of the more common questions women ask.

Do breasts hurt when they grow? If so, why?

Yes, breasts can hurt when they grow. Breasts grow in response to the hormones estrogen and progesterone. As you enter puberty, levels of these hormones increase. Your breasts begin to grow under the stimulation of these hormones. Hormone levels also change during the menstrual cycle, pregnancy, breastfeeding, and menopause. Hormones cause a change in the amount of fluid in your breasts. This may make your breasts feel more sensitive or painful.

Should my breasts be the same size?

Most women have variances in the size of their breasts. It’s normal for a woman’s breasts to slightly differ in size, or even vary by whole cup sizes. This is especially common during puberty, when your breasts are still growing. Even a large difference in size is generally not a health concern.

Does a lump in my breast mean I have breast cancer?

While performing breast self-examinations to look for lumps in your breast can help in early cancer detection, lumps don’t necessarily mean you have cancer. The main reason self-exams are important is that they help you learn what is normal for you. For many women, having some lumps is normal.

With regular examination, you may notice that your lumps come and go, usually with your menstrual cycle. Although most lumps aren’t a cause for concern, whenever you find a lump for the first time you should let your doctor know. Some lumps will need to be drained or possibly even removed if they become uncomfortable.

Other changes in your body may signal that your breasts are, or are about to, start growing. Some signs include:

  • the appearance of small, firm lumps under your nipples
  • itchiness around your nipples and chest area
  • tender or soreness in your breasts
  • backaches

Breasts develop in stages of a woman’s life — the time prior to birth, puberty, childbearing years, and menopause. There will also be changes in breast development within these stages during menstruation as well as during pregnancies.

Birth stage: Breast development begins while a female baby is still a fetus. By the time she’s born, she will have already started forming nipples and milk ducts.

Puberty stage: Normal puberty in girls can start as early as 8 years old and as late as 13 years old. When your ovaries start creating estrogen, this results in your breast tissues gaining fat. This additional fat causes your breasts to begin to grown larger. This is also when the milk ducts grow. Once you start ovulating and having a menstrual cycle, the milk ducts will form glands. These are called secretory glands.

Menopause stage: Usually women begin to reach menopause around age 50, but it can start earlier for some. During menopause, your body won’t produce as much estrogen, and that will affect your breasts. They won’t be as elastic and may decrease in size, which can cause sagging. However, if you’re being treated with hormone therapy, you may experience the same symptoms you had during menstrual cycles.

Development of the breasts also varies for those going through gender transition. It happens gradually, so if you’re undergoing transition, don’t expect an immediate change. It usually takes years to fully develop breasts through hormone treatment.

Your breasts might be uneven during development and even after they’ve fully developed. This is completely normal for any woman.

It’s important to note that you shouldn’t try taking more estrogen than prescribed to make your breast development go faster. More estrogen won’t increase development and can be extremely dangerous for your health.

More research is needed for breast cancer in transgender women. However, it’s important that you follow recommended guidelines for all women when it comes to your breast health and breast cancer. Talk to your doctor about the best ways to screen for breast cancer.

Soon after your breasts develop, you should start performing regular breast self-examinations. You can ask a medical professional the proper way to check your breasts, but it’s simple and can be done in a few minutes at home. Regular breast self-examinations can also help you become more familiar with your breasts, so it will be easier to notice any changes. Discuss any changes with your doctor.

Caring for your breasts once they develop is important and can help avoid some of the pain they might cause. For instance, wearing a bra gives your breasts support and comfort. If you run or participate in sports, you may want to wear a sports bra to give them extra support and help avoid injury and discomfort.

Throughout your life, your breasts will go through changes after they’ve developed. These times include your monthly menstrual cycle as well as pregnancies.

Menstruation cycle changes

Each monthly cycle will cause changes in your breasts due to hormones. Your breasts may become larger and sore during your cycle, and then return to normal once it’s finished.

Pregnancy changes

During pregnancy, your breasts will begin getting ready to produce milk for your baby, which is called lactation. This process will create several changes to your breasts, which can include:

  • areolas swelling, darkening, and increasing in size
  • swollen breasts
  • soreness along the sides of your breasts
  • a tingling sensation in your nipples
  • blood vessels in your breasts becoming more noticeable

You should always see your doctor if you find a new lump or a lump that gets bigger or doesn’t change with your monthly cycle. Check with your doctor if you have a spot on your breast that is red and painful. This could be a sign of infection that will need medication.

Be sure to contact your doctor if you have any symptoms of breast cancer. Some of these are:

  • a discharge from your nipple that isn’t milk
  • swelling of your breast
  • irritated skin on your breast
  • pain in your nipple
  • your nipple turning inward