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How Your Breast Changes Throughout Your Monthly Cycle

Mira Adora
How Your Breast Changes Throughout Your Monthly Cycle how to adjust it for your monthly needs.
Why should you know about your breast changes throughout the month? First of all, it helps make you aware of changes in your body. If you don’t know about the regular changes of your breasts, you might panic over lumps or the changing sizes. And second, knowing about how your breast changes helps you know the right time to check your bra size and how to adjust it for your monthly needs.

Phase 1: They’re lumpy

This might be the scariest phase for you, especially if you’ve heard horror stories about lumps or you just started having your menses. You might be surprised to know that this is completely normal, and there is a perfectly reasonable scientific explanation for it.

Some women, right before their periods, have fibrocystic lumps in their breasts that swell because of the hormone changes. You might feel them while taking a shower, or (if you are very sensitive) even while adjusting your bra.

If you feel lumps in your breasts, mentally check how close to your period you might be. If it’s at the right phase, just before your period, you might want to wait until after your period to see if the lumps persist.

Phase 2: They’re softer and smaller

As your period reaches the end of its cycle (usually around 7 days), you might notice that your breasts are getting smaller and just the slightest bit saggy. Again, this is a normal part of the cycle. During ovulation and leading up to your period, there is a build up of both estrogen and progesterone in your breasts. These hormones trigger small lumps in the breasts, and also cause your breasts to swell.

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During your period, both estrogen and progesterone in your breasts drain away, and you’ll notice your breasts get smaller and softer. Your body is recovering for the next monthly cycle. If the change happens at any other stage of the cycle, however, you might want to get it checked, just to be safe. This is also probably the time that you go back to your regular bra sizes from your period bra, if you keep a special stockpile for that part of the cycle.

Phase 3: They’re perky

In the phase leading up to ovulation and during ovulation, there is a build up of estrogen in your breasts. It’s a healthy build up, swelling the breasts and making the skin more elastic, and therefore perkier. That’s good, right? Well, yes! If you are planning a photoshoot or a nice dress- up, there will never be a more perfect time of the month. If your periods are regular, you are in a perfect position to plan for the future.

It might sound shallow, but it’s all part of the normal monthly cycle. Another good, healthy outcome of noticing your perky breasts is that it prepares you for the next stages leading up to your period. Since you have the cycle down pat in your head, you can already anticipate what you need to look out and prepare for in the cycle.

Phase 4: They’re full and firm

Yes, we’ve been throwing these words around, but they are very important to understanding how your breasts change and go through different cycles. Estrogen makes your breasts elastic and perky during ovulation. After the ovulation period is done, you’ll notice that your breasts don’t get any smaller, but they will change shape and become fuller and firmer. 

This happens because the estrogen level begins to drop after ovulation. The other hormone, progesterone, starts to build up. Progesterone is the hormone that helps the body get ready for a possible pregnancy. As a result, the breasts begin to grow and sometimes the milk ducts swell in preparation to receive a baby and breastfeed them. If you aren’t pregnant, the progesterone will just continue to build up until your period. Then and only then, as we noted in Phase 2, will both estrogen and progesterone levels start to drop. 

Phase 5: They’re lopsided

It is quite normal for one breast to be smaller than the other. Our breasts are made of fat, and usually the breast on the side of the dominant hand will be smaller because more fat is “burned” in normal daily tasks. However, as the monthly cycle moves from part to part, you may notice your breasts becoming more lopsided than usual. Unless there is a very drastic and notable change within a short period of time, this is normal.

During ovulation, your breasts will be the most symmetric compared to other parts of the monthly cycle. Any other time, expect some lopsidedness as your breasts swell with progesterone, lump before your period, or soften right after your period. Your breasts won’t change size at the same rate, always leaving some lopsidedness in the mix.


There’s nothing to fear, as long as you know what you are looking for. Have a fun and healthy month!


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Mira Adora is a freelance writer from the US. She loves sharing knowledge and interests related to technology, business, and travel by making herself busy producing content. When not working, she binges Netflix.


DISCLAIMER: The views expressed in this article are those of the author and do not necessarily represent or reflect the views of Nannocare. Nannocare is not affiliated, associated, authorized, endorsed by, or in any way officially connected with the author of this article, or any of its subsidiaries or its affiliates. 

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