Your breasts during pregnancy

Your breasts during pregnancy
Many women notice a change in their breasts when they’re pregnant.

Many women notice a change in their breasts when they’re pregnant. This can be one of the first signs of pregnancy, and it means that your breasts are preparing for breastfeeding. Breasts can produce milk between the fourth and sixth month of pregnancy.

Increase in breast size and sensitivity

During the first 12 weeks of pregnancy, your body produces certain hormones that change the appearance of your breasts. Progesterone is the main hormone responsible for the growth of your mammary glands, which will produce milk. Estrogen controls the growth of milk ducts, which transport the breast milk.

If you have had a breast injury or surgery, it’s a good idea to meet with a lactation consultant during your pregnancy to assess any potential impacts on breastfeeding.

These transformations explain the increase in breast size during pregnancy. You may notice that your breasts swell in the first few weeks. They will continue to grow and become heavier throughout the second and third trimesters.

However, it’s important to know that breast shape, size, and colour can vary widely from one woman to another. A woman’s two breasts can also be different from one another.

Furthermore, breasts require a lot of blood to transport the nutrients that will make up the milk. Blood volume increases by 50% during pregnancy. After the 16th week of pregnancy, the veins near the surface of your breasts will become more visible.

The formation of cell clusters responsible for producing milk and the development of the milk ducts can make breasts more sensitive in early pregnancy. You may also experience tingling, burning, or itching. This sensitivity will decrease as the pregnancy progresses.

Rapid breast growth can cause stretch marks, especially during the sixth and seventh month of pregnancy. They will fade and become less noticeable after you give birth. Some women use creams to reduce the appearance of stretch marks, but there is no research to support their effectiveness.

Changes to the nipples

During the second and third trimesters, the areolas (areas surrounding the nipples) become darker and slightly larger. This change will diminish once you finish breastfeeding.

You will also notice small bumps popping up around the areolas. These are called Montgomery glands or Montgomery tubercles. These glands produce an oily substance that lubricates the areolas. The scent also mimics that of amniotic fluid and may help attract the baby to the breast. Many mothers notice that their nipples start to stick out more.

Some experts believe that all of these changes are meant to help the newborn locate the nipple and latch on more easily.

Some women may discover a lump in one of their breasts during pregnancy. In most cases, the lump is a small buildup of milk caused by a blocked duct or a benign tumour. However, it is always best to tell your doctor if you find one.


Starting in your fourth month of pregnancy, you may notice a yellowish fluid flowing from your nipples. For some women, this happens in the last trimester. Discharge is usually more frequent when the breasts are stimulated.

This liquid is called colostrum and is rich in antibodies. Colostrum is the first milk that a breastfed baby will receive at birth and during their first few days of life. Colostrum has important properties that help protect the baby from infection.

Some women do not experience discharge during pregnancy. This is nothing to be worried about and does not mean that breastfeeding will be more difficult.

Tips for staying comfortable

Beginning in your second trimester, the growing size and weight of your breasts may require a larger, more supportive bra. An increase of one to two bra cup sizes is normal. You can also wear your bra at night if you need extra support.

Choose a bra that is large enough and has wide straps, no underwire, and no seams near the nipple. Sports bras or nursing bras are a good option.

If your breast skin is sensitive or itchy:

  • Avoid hot baths or showers that can dry out your skin
  • Use a towel to blot up excess moisture after bathing

If you are experiencing colostrum discharge, try placing breast pads (nursing pads) in your bra to help absorb the fluid. Opt for cotton or paper pads without plastic liners and swap them out often.

Things to keep in mind

  • Breasts increase in size and become more sensitive during pregnancy.
  • Nipples can also change in appearance.
  • These changes help prepare your body for breastfeeding after the baby is born.


Naître et grandir

Scientific review: Louise Godin, graduate nurse and lactation consultant, IBCLC
Research and copywriting: The Naître et grandir team
Updated: March 2021

Photo: 123rf/mbudley



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