How Your Breasts Can Change During Pregnancy

Are you pregnant, or hoping to be? Have you noticed some changes in your breasts and are wondering whether or not they’re normal?

Breasts are used for nursing your baby after he or she arrives, but to do that they go through a whole lot of changes throughout your pregnancy. Breast changes can be one of the first indicators you’re pregnant and can clue you into the excitement before you even take your first pregnancy test.

Before now you likely haven’t thought of your breasts as much more than a part of your female anatomy, but they’re about to become a whole lot more functional. Here’s what you need to know about what happens, why it happens, and when to expect certain breast changes throughout your pregnancy.

Why Do Breasts Change During Pregnancy?

When most people think of physical changes during pregnancy, they envision a woman’s expanding belly. But the reality is the whole body undergoes a radical transformation, and the breasts are no exception.

Breast changes during pregnancy occur due to (source):

  • Hormonal shifts: Hormones contribute to fat storage, water retention, and changes in sensitivity, all of which can affect your breasts. And not only “pregnancy hormones” are to blame. When you’re pregnant, even “regular” hormones like cortisol and insulin shift, resulting in significant bodily changes.
  • Weight gain: Because the breasts are primarily made up of fat, it makes sense that as you put on, weight during pregnancy some of that weight would go to your breasts. While you might try to limit the number of pounds you put on thanks to increased body fat, the fact is that it’s normal. You can expect that up to seven pounds of the weight you put on during pregnancy is due to increased fat storage, and it’s inevitable that some of that will end up in your breasts (source).
  • Expanding rib cage: As your baby grows, your rib cage expands to accommodate it. While this doesn’t technically enlarge your breasts, it can make them seem larger. It will also affect your bra size, as your previous band size will start to feel uncomfortable the further along you get in your pregnancy.
  • Swelling: You know your fingers swell during pregnancy. But did you know your breasts do, too? There are hormones that specifically cause your breast tissue to swell, making them increase in size by as much as two cup sizes.
  • Milk production: Even though your milk production won’t fully ramp up until after your baby is born, your body is getting in gear well before your little one arrives. These changes can not only result in increased volume, but some women also experience leakage. Whether you see it or not, your breasts are preparing to nourish a baby, and this can affect the way your breasts look and feel.

What Are the Parts of the Breast?

Before going into the details about specific changes you may experience during pregnancy, it’s important to understand the parts of the breast.

The breasts aren’t just in the center of your chest. They start right below the collarbone, go through the underarm and across the middle of the rib cage (source). They are primarily composed of fatty tissue.

Within the breast are areas called lobes. These are each composed of a collection of lobules, which are the milk-producing glands. Milk is carried from the lobules to the nipples through ducts.

The darker area around the nipple is called the areola. On the areola, you may have noticed bumps. These are called Montgomery’s tubercles — they secrete oil to help lubricate the nipple during pregnancy and breastfeeding (source).

The Takeaway

When you look at the anatomy of the breast, it’s clear their primary function is to produce milk and nurse your baby. With this in mind, it shouldn’t be surprising they undergo huge changes during pregnancy as they prepare to do so.

6 Breast Changes to Expect During Pregnancy

You can expect your breasts to change in a number of ways during pregnancy, including:

1. Size

The stored fat, swelling, water retention, milk production, and expanding rib cage all contribute to an increase in your breast size during pregnancy. You can expect your breasts will increase in weight by as much as two pounds (source).

2. Firmness

Many women blame nursing for breasts that are not as full, firm, and perky as they once were. However, that myth has been scientifically debunked, and the true long-term breast changes are due to pregnancy itself (source). This is due to the changes in size and the stretching of the skin and ligaments.

  • The Bad News: Pregnancy will change your breasts over the long term.
  • The Good News: You can breastfeed with confidence, knowing it’s not to blame for sagging breasts.

3. Appearance

Aside from appearing bigger, there are more specific changes you may notice in your breasts throughout pregnancy. You may notice the veins that run along the sides of your breasts are more prominent or appear darker. This is due to increased blood flow to your breasts.

Some women develop stretch marks along the sides of their breasts. These usually occur later in your pregnancy, but can occur at any time.

You may also notice bumps on your areola. They have always been there. They just tend to get noticeably larger when you are pregnant.

Learn More
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4. Nipple Color

Along with the tubercles or bumps on your areolas, you will likely notice your nipples and the surrounding areas become much darker. This happens fairly early in pregnancy, and the coloring will remain throughout your pregnancy and possibly even through the time you breastfeed.

For some mothers, the dark color fades shortly after birth. Either way, the darkening is not permanent.

5. Discharge

As early as four or five months into your pregnancy, you may notice discharge from your nipples. This is colostrum, the earliest, nutrient-rich substance you’ll produce for your baby the first few days after birth before your milk comes in. This is just your breasts gearing up to feed your wee one.

But if you don’t experience discharge, don’t worry. There does not appear to be a correlation between prenatal nipple discharge and postnatal milk production. You’ll still be able to feed your baby (source).

6. Sensitivity

Your breasts may be tender or sensitive throughout your pregnancy, but this feeling could wax and wane. It also doesn’t have to be in areas where you typically experience breast tenderness. If you usually experience tenderness on the sides of the breast, you may suddenly develop sensitivity in your nipples.

You may also experience itching or a sensation of irritation, similar to the way your belly feels toward the end of your pregnancy as the skin gets stretched to the max.

You may wonder how you’ll be able to nurse when your nipples are so tender, particularly if this is your first pregnancy. I used to tell women planning to breastfeed to “twirl” their nipples to gently coax inverted nipples into being more ready for breastfeeding but also to help them become accustomed to having tension placed on their nipples. Newborn babies do not suckle gently!

Headshot of Christine, Traxler, MD, BS

Editor's Note:

Christine Traxler, MD, BS

Are Breast Changes a Symptom of Early Pregnancy?

Breast tenderness is a common complaint of early pregnancy. It’s due to the hormones estrogen and progesterone, and can feel like:

  • Bruising.
  • Nipple tingling.
  • General sense of heaviness of the breast.
  • Pain in the lymph nodes under the arm.
  • Overall sensitivity.
  • Tenderness localized to specific areas.

One of the problems with using breast tenderness as a way to identify an early pregnancy, however, is that these symptoms are nearly identical to symptoms many women experience immediately before menstruation.

This Is a More Reliable Pregnancy Sign

A symptom that is a much better indicator of pregnancy is the darkening of the areolas. This darkening isn’t subtle — it’s a significant, noticeable change that occurs, and your areolas even get a bit larger.

This can happen as early as a week after conception (source), so it may even be noticeable before you take a pregnancy test. The exact reason for this change isn’t known, but many speculate it’s to help your baby see your nipples more easily when they feed.

How Many Cup Sizes Will I Gain?

As your entire body expands and your pregnancy progresses, you may wonder about what’s normal and what’s not. The truth — as with most things pregnancy-related — is that it depends.

While it’s practically a guarantee your breasts will grow, there’s no telling how much. Some women grow two cup sizes throughout their pregnancy and keep the increased volume for the duration of their time breastfeeding.

Other women experience some enlarging during their pregnancy, but their breasts revert to their pre-pregnancy size shortly after childbirth.

This lack of consistency can make it difficult and frustrating to shop for nursing or maternity bras, especially when you don’t want to overspend on items that may not work for you long-term.

Some ways you can compensate for this include:

  • Buying only one or two bras at a time and rotating through them until they are no longer comfortable.
  • Choosing soft, elastic bras, often known as night nursing bras.
  • Using a bra extender if your cup size still fits but your band does not.

The Bottom Line

During pregnancy, your body is doing way more than just growing a baby. It’s also preparing your body to nourish that baby for an extended period, which means your breasts have to get ready, too.

From your very first week of pregnancy through your postpartum period, you can expect to experience significant breast changes, including:

  • Increased breast size.
  • A change in firmness or perkiness.
  • Noticeable bumps on your areola.
  • A darkening of the areola or nipples.
  • Increased veining in your breasts.
  • Increased breast tenderness or nipple sensitivity.
  • Discharge from the nipples.

Some of these changes are only temporary due to pregnancy, while others may be longer lasting or even permanent.

What breast changes are surprising you the most during your pregnancy? Let us know about your experience down in the comments section below.

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