How Your Breasts Change Throughout the Menstrual Cycle

You’re committed to your health, including your breast health. That’s why you schedule breast screening exams as part of your well-woman routine. 

You also perform monthly self-exams. You notice that performing self-exams 3-5 days after your period ends is recommended. Why?

During the menstrual cycle, your breasts undergo changes., including drastically changing how they look and feel  

Our breast experts, Joseph Calandra, MD, and Karen Mass, MD, at Mass Medical Imaging, encourage you to become familiar with how your breasts change during the month. Our Lake Forest, Illinois, office also performs your annual breast screenings, including a mammogram, depending on your age and other factors.

How and why do your breasts change during your cycle? 

Why your breasts change during your cycle

Your menstrual cycle is regulated by the level of hormones circulating throughout your body. These hormones influence your breasts, too.

Early in your cycle, your body produces more estrogen than normal. Your estrogen peaks at about the middle of your cycle (which begins the day after your last period ends). Estrogen causes your breast ducts to grow.

Progesterone peaks at about day 21 in a 28-day cycle. Progesterone makes your milk glands grow. These hormonal changes account for why your breasts look and feel different at different times.

Your breasts get bigger and smaller

After ovulation (i.e., when an ovary releases a mature egg), at around day 15, you enter the luteal phase of your cycle, which usually lasts until your cycle ends. That corresponds to increased progesterone, which makes your breasts feel fuller.

Your breasts swell like this because they’re preparing to nourish a new life. However, if you don’t get pregnant, your breasts get smaller as your cycle ends.

Your breasts may feel lumpy

One reason why it’s best to wait a few days after your period ends before conducting a breast self-exam is that your breasts may feel temporarily lumpy. That can be confusing or even frightening when you’re checking for cancerous lumps.

The lumpy feeling that occurs during your cycle is a normal change. You’ll most likely feel this lumpy or dense sensation just before your period starts. The lumps may be limited to the outer areas of your breasts.

Sometimes, your breasts may feel lumpy throughout your cycle. In that case, you could have a benign condition called fibrocystic breast disease. 

Your breasts may be tender and painful

As your breasts swell, they may also feel tender. They may also ache. Again, these are perfectly normal changes.

Wait until after your period ends before examining your breasts. You must palpate them physically; doing so when they’re still tender could be too painful.

Some changes aren’t normal

One of the best reasons to conduct a breast exam every month is that you become more aware of your breasts and what’s normal for them. You may notice, for instance, that one is higher than the other. Or one might be bigger than the other. Contact us if you notice troubling changes, however, including:

• A new lump or lumps
• Lumps have changed or grown
• Lumps only on one breast
• Nipple discharge
• A rash or other changes
• One of your nipples is inverted (i.e., turned inward)
• The skin on your breasts dimples or puckers
• A nipple has changed position

Call our friendly team or use our online appointment form today to schedule your annual breast screening, or have us look into a change that concerns you.