How your breasts change in pregnancy, week by week

Some of the most common breast changes include tenderness and increased sensitivity, along with a boost in in size and perhaps stretchmarks. And, as your blood volume increases by around 50 per cent during pregnancy (to supply your baby with oxygen and nutrients) you may notice the veins in your breasts becoming larger, bluer and more prominent.

Every woman experiences pregnancy differently and you may notice some of these changes more than others. If this is not your first pregnancy, you may find the changes are the same as during your last pregnancy or quite different.

Please be reassured that noticing – or not noticing – changes in your breasts does not signify any problem or issues with your pregnancy or with your ability to breastfeed.

How your breasts change in the 1st trimester of pregnancy (weeks 0 to 12)

Your levels of the hormones oestrogen and progesterone rise during pregnancy, preparing your breasts to be able to produce milk for your baby. Increased blood flow to your breasts, and the beginnings of changes to the milk ducts and glands (called lobules) within your breast tissue, will start to make your breasts grow in size. You may notice this breast growth in your 1st trimester or you many not notice any change until later in your pregnancy: whichever happens to you, it's quite normal.

Many pregnant women in their 1st trimester experience the following breast changes:

• Breast tenderness. This is often one of the 1st signs that you are pregnant. You may notice tenderness even before your period would have been due or before you take a pregnancy test. As well as feeling tender, your breasts may feel sore or heavy, and you may feel discomfort or sensitivity if you lie on your front to sleep. This tenderness and discomfort enerally improves after a few weeks, as your body adapts, though it can recur later in your pregnancy.
• Tingling sensation in your breasts. This may be due to increased blood flow.
• Tenderness and discomfort extending up into your armpit. Breast tissue actually extends right up into the middle of your armpit – this part of your breast is called the Tail of Spence – so if the circular body of your breasts over your chest is tender, this extended area may well be tender, too.
• More sensitive nipples. Your nipples can feel more sensitive than usual, or painful when they're touched.
• Your breasts may start to grow even this early on in your pregnancy. This will continue throughout your pregnancy (and beyond if you breastfeed) and may be most noticeable if this is your 1st pregnancy. You may notice that you increase in both band and cup size.
• Itchy breast skin. As your breasts grow, especially if they grow quickly, the skin has to stretch and the skin over your breasts can feel itchy and uncomfortable as it stretches. Keeping the skin well-moisturised can ease any itching.
• Stretchmarks can start to appear as your breasts grow. On pale skin tones, these can be pink, red or purple at first but over time will change and fade to become lighter and perhaps silvery in colour. With dark skin tones, stretchmarks can look darker or lighter than the rest of the breast skin.
• More visible blue veins. The amount of blood in your body is increasing, and so your blood vessels will dilate (get wider). This means you may become aware of more prominent, blue veins on your skin, often more visible on your breasts than elsewhere.

How your breasts change in the 2nd trimester of pregnancy (weeks 13 to 27)

If you didn't notice any breast growth in the 1st 3 months of your pregnancy, you may well start to notice it during this 2nd trimester. You may also notice some changes to the area around your nipples.

Many pregnant women in their 2nd trimester experience the following breast changes:

• Your breasts may continue to increase in size
• Your areolas (the area around your nipples) often grow larger and darker. The colour often returns to its pre-pregnancy shade after you've had your baby and/or finished breastfeeding but it may also remain slightly darker than it was before your pregnancy.
• The small bumps on your areola may become more prominent. These bumps, called Montgomery's tubercles, are the glands which produce anti-bacterial lubrication for your skin and nipples, ready for breastfeeding. The smell of the secretions produced by these tubercles may even help your baby find your nipple to latch on.
• You may notice some yellowy-white discharge from your nipples. This is more common in the 3rd trimester. The discharge is actually colostrum, the nutrient-rich milk your breasts produce for your baby's very first feeds.

How your breasts change in the 3rd trimester of pregnancy (weeks 28 to birth)

It's during this 3rd trimester that your breasts should become fully ready and able to produce milk, with the hormones oestrogen and progesterone stimulating the further development of your milk ducts and milk glands (lobules). Oestrogen also has a role in stimulating the production of another hormone called prolactin, which further stimulates breast growth and the production of milk.

Many pregnant women in their 3rd trimester experience the following breast changes:

• Your breasts continue to grow, becoming heavier.
• Your nipples and areolas can continue to grow in size and become darker in colour.
• Colostrum may leak from your nipples. Colostrum is the name given to the first milk your breasts produce. It is thick and yellowish in colour, is high in nutrients and antibodies and has a role in the development of your baby's immune system. Colostrum discharge during pregnancy is more common after nipple or breast stimulation but can occur on its own.
• Stretchmarks can continue to develop or become more noticeable. You can use a simple moisturising product, if you feel the skin on your breasts is dry or itchy.

How your breasts change post-partum (after you've given birth)

After the delivery of your baby, your levels of oestrogen and progesterone fall relatively rapidly, while your levels of the hormone prolactin continue to rise. Whether you choose to breastfeed or not, your breasts will undergo changes during this stage.

• Your breasts produce colostrum after delivery.
• Between 5 days and 2 weeks after delivery, your breasts produce milk instead of colostrum. Your breasts may further increase in size due to the production of milk.
• If you don't breastfeed, your breasts often return to their pre-pregnancy size, though this is also dependent on weight gain.
• The colour and size of your nipples and areolas may return to their pre-pregnancy state, though not always. And this can take months, even if they do.
• If you breastfeed, your beasts may only return to their original shape and size once you stop but they may also remain larger than before. Either is normal.
• You may feel your breasts sag more than they did when you were pregnant. This may be more likely if your breasts were larger in size before your pregnancy, if you are overweight or obese or had significant weight changes during pregnancy. This is also more likely if you have had multiple pregnancies and/or if you smoke. Moisturise your breasts regularly to help the skin's elasticity.

This is an edited extract from Breasts: An Owner's Guide by Dr Philippa Kaye, published by Dorling Kindersley Ltd.

Please note: this advice is not personalised or meant to replace individual advice given to you by your doctor or medical team.

Pic: Getty. Illustrations: Dorling Kindersley: Lauren Mitchell and Hannah Naughton

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