When do your boobs start growing during pregnancy

You'll notice some changes in your breasts as your body gets ready for breastfeeding your baby.

Table of Contents Show

Early stage
Later stage
When to see your GP
Breast lumps
Important
Blood from nipples
Preparing for breastfeeding
Connect with your local breastfeeding group
Healthy eating
Pregnancy bras
The First Signs of Pregnancy
Breast Enlargement
Finding a New Bra for Your Pregnancy Breasts
Itching Breasts
Breast Tenderness
Colostrum Production

Changes to breasts during pregnancy

Early stage

Your pregnancy hormones cause normal breast tissue to change into milk-producing tissue. This change happens as early as the first trimester (week 1 to week 12).

Early on in the pregnancy, you may notice a tingling sensation in your breasts. Your breasts may feel tender and sore. This is due to increasing levels of the hormone progesterone.

Later stage

As your pregnancy progresses, your nipples and the areola (the area around the nipples) may darken in colour.

The veins on the surface of your breasts may become more noticeable. You may also notice stretch marks on your breasts.

From about 16 weeks your breasts are ready to start producing milk. This is colostrum (first milk). It's yellow in colour and is sometimes called 'liquid gold'.

Your breasts may leak colostrum and you may be able to express small amounts. But there's no link between producing colostrum in pregnancy and your milk supply after the birth.

In the last few weeks of pregnancy, your nipples and your breasts become larger.

When to see your GP

Breast lumps

You can sometimes get breast lumps during pregnancy. Most of the time, these are benign and caused by hormonal changes.

Breast cancer is uncommon in younger women and uncommon during pregnancy. But you should always get breast lumps checked by your GP.

If you have an existing lump that changes during pregnancy, get this checked too.

Important

Always get new breast lumps or existing lumps that have changed checked by your GP

Blood from nipples

Sometimes blood-stained fluid may leak from your nipples. This may be normal - but it's very important to see your GP or breastfeeding specialist if you notice blood-stained nipple discharge.

Most of the time this happens due to increased blood flow and rapid development of milk producing glands. It can also be caused by trauma to the breast or nipples.

This is commonly known as 'rusty pipe syndrome' and usually disappears after a few feeds.

Preparing for breastfeeding

Your breasts get ready during pregnancy by making milk for your baby.

Becoming familiar with and handling your breasts during pregnancy is an important part of preparing to breastfeed your newborn.

Continue your breast self-examination during pregnancy. This will help you become more familiar with your breasts.

You can read practical tips for breastfeeding to help you build your confidence. These tips will help you to know what to expect when feeding your new baby.

Connect with your local breastfeeding group

Some women find it helpful to join a breastfeeding support group during pregnancy. You can meet other new mothers and hear about their experiences.

Find a breastfeeding support group near you

You can discuss all aspects of breastfeeding with your midwife, public health nurse, GP practice nurse or GP. If you have any concerns, they can refer you to an infant feeding specialist before the birth of your baby.

Healthy eating

A healthy diet and normal fluid intake is important when you're breastfeeding. You do not need to follow a specific diet.

Learn more about what to eat while you're breastfeeding

Pregnancy bras

As your breasts grow you should make sure your bra is well-fitting and not too tight. Let comfort be your guide.

To find a well-fitting bra, make sure:

it is not too tight or loose
it is not wired or padded
the strap at the back does not cut in to your skin
your breasts fill the fabric of the cup with no loose fabric - there should also be no bulging over the top, at the sides or underneath
the shoulder straps stay in place without digging in to your skin
the strap around the back and the front underband lies close to your body and is roughly at the same level

You can find good quality pregnancy and nursing bras in many shops. Ask the shop assistant to help you find the right fit. You can also buy maternity bras online.

If you usually go without a bra, there is no need to wear one during breastfeeding.

Page last reviewed: 10 April 2022
Next review due: 10 April 2025

Your belly usually takes center stage in your pregnancy, but a whole lot of changes are happening in your breasts, too. Even before that plus sign pops up on your pregnancy test, hormonal changes are preparing your breasts to feed your baby-to-be.

Those changes affect women to different degrees, so while you may experience some major breast changes – including a surprising pregnant squirt here or there – other women may notice few differences, according to the American Pregnancy Association. To avoid any surprises during your nine-month journey, here a few things to look for.

The First Signs of Pregnancy

Surprise—that soreness in your breasts may not be PMS after all! About 10 days after conception, your placenta starts releasing human chorionic gonadotropin (hCG), the hormone that kicks off estrogen and progesterone production (hCG is what turns the pee stick positive in a pregnancy test). All those hormones kick-start the development of the milk glands in your breast, so your boobs may know you're expecting before you do, explains Erika Nichelson, M.D., an Ob-Gyn at Mercy Medical Center in Baltimore. "I was probably about half a second pregnant when I noticed that my breasts were extremely sensitive," recalls Dawn, 40, a mom of two in New York. "The slightest breeze on my chest made me wince!"

Breast Enlargement

For good or bad, your breasts are going to get bigger – and they're going to do it quickly. Throughout the first three months of pregnancy, fat builds up in the breasts and the milk glands increase in size, says Alana Bibeau, Ph.D, a doula and a member of the Rhode Island Birth Network Board of Trustees. By six weeks into pregnancy, many women's breasts have grown a full cup size or more. And by nine months, the average woman has gained two pounds just in her breasts, according to the March of Dimes. (But if you're eagerly awaiting bigger boobs and they never appear, don't worry, says Dr. Nichelson. "I've had three children, including twins, and my breasts never got bigger," she explains. "Everyone is different and size doesn't necessarily matter when it comes to breastfeeding.)"

Finding a New Bra for Your Pregnancy Breasts

If your trusty 34Bs suddenly feel as tiny as a training bra, and your favorite lingerie feels soft as sandpaper, get yourself to a maternity store. A proper bra is crucial to relieving the new weight and supporting your back. Olivia Capone Myers, style director at Destination Maternity, suggests you get fitted for maternity bras as soon as your breasts begin to grow in their first trimester: "Looking for at least three to four hooks in the closure to ensure comfort throughout your pregnancy, and make sure it fits on the tightest hook when you buy it so you can loosen it as your body grows," she recommends.

Also look for a maternity bra with a thick band (no underwire!) beneath the cups and wide shoulder straps. Opt for cotton bras over synthetic ones; they're more comfortable because they allow the skin to breathe, suggests the March of Dimes. Capone Myers also recommends buying a sleep bra, which will gently support your girls at night during pregnancy and when you begin nursing.

Remember that one bra run is not enough. Your breasts will keep changing throughout your pregnancy – and so should your bras!

Itching Breasts

Your bra isn't the only thing that has to stretch to accommodate your larger breasts – your skin does, too. Relieve itching and prevent stretch marks by applying moisture-rich creams and cocoa butter. "Ice packs, over-the-counter Benadryl cream, or menthol-based moisturizers can help with discomfort when the skin is itchy from growth," says Tsipporah Shainhouse, M.D., a Los Angeles dermatologist who works extensively with pregnant women.

Breast Tenderness

Ah, the irony: As your breasts get more bodacious, your partner may be eager to explore your new curves, but sore nipples can make your boobs a no-touch zone. (Though some women find the new sensitivity actually enhances sex.) If your breast tenderness is accompanied by one or more red, tender-to-the-touch, hard lumps, don't panic. As milk ducts grow and fill throughout pregnancy, it's not uncommon for women to suffer from clogged milk ducts. Warm compresses, baths, and massage can often clear the duct in a few days. If you also feel achy, run-down, and feverish, call your doctor: Your clogged duct might have become infected. Also, keep in mind that although breast cancer is rare among women younger than 35, women older than 35 should talk to their doctor about having a breast cancer screening before trying to become pregnant.

Colostrum Production

As your body gets ready to feed your baby, you may start dripping colostrum (the nutrient-dense liquid your breasts produce before your milk comes in) days, weeks, or even months before there's a baby around to lap it up. The sweet and watery pre-milk is most often seen on pregnant women's shirts.

Sometime between the end of the first trimester and the third trimester, breasts begin to produce the thick and yellow liquid, which later becomes pale and almost colorless, and provides newborns protection against disease and bacterial infection during the first few days of life, Bonnie Herbst, R.N., a board-certified lactation consultant at The Ohio State University Medical Center. Rich in protein and antibodies, colostrum has less fat and sugar than mature milk, which comes in a few days after delivery.

Many women experience pregnant squirts in which they leak small amounts of colostrum, but others just find dried colostrum on their nipples, and others notice nothing different. All of these are within the range of normal, Bibeau says. Discharge may occur at any time or when stimulated through massage or sexual arousal. If you're worried about colostrum leakage, you can wear disposable or washable breast pads, Bibeau says. Allow your breasts to air-dry a few times each day and after showering.