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Breast changes from the beginning of pregnancy to the end of breastfeeding

Medela's experts explain the changes that occur in the breast from the beginning of pregnancy to the end of breastfeeding, as well as tips for taking care of your breasts throughout this period.

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From the moment of conception, your body begins to prepare for the birth of your baby. This applies not only to the uterus - the anatomy of the breast also changes radically. This article will tell you what to expect in each trimester, during and after breastfeeding.

First trimester breast changes

Early in pregnancy, many women notice changes in their breasts. Moreover, often they become the first signs of pregnancy. Fluctuations in hormone levels and changes in the structure of the mammary glands can cause increased sensitivity and soreness of the nipples and breasts as early as the third or fourth week. For some pregnant women, breast tenderness persists until childbirth, but for most it goes away after the first trimester.

“Sometimes during pregnancy, breasts grow very quickly in the first weeks, and sometimes their size increases gradually,” says Dr. Jacqueline Kent, a leading lactation specialist at the University of Western Australia. “All women are different. For some, breast size may not change much until childbirth or even after them. In general, we can say that by the time the milk arrives, the breast will most likely become one and a half times larger than before pregnancy! ¹

As soon as your regular bras start to feel tight (usually around 12 weeks), it's time to buy a maternity bra. The most comfortable, according to many women, are seamless models with wide straps made of soft, breathable fabric. It is best to avoid underwired bras as they can put pressure on the developing milk ducts.

It is important to take your measurements correctly in order to find the right bra with a good fit. Take measurements every couple of months, as you may need a different size bra as your baby grows and your breasts get bigger.

Breast changes in the second trimester

From about the 15th week of pregnancy, newly formed cells that produce milk are activated in the breast, and by about the 22nd week, production begins. ¹ But don't worry - most of this milk will be absorbed by the body without going out, as pregnancy hormones prevent it from being overproduced or excreted.

“During the second trimester, you may notice that the nipples and areolas (the areas of skin around the nipples) become darker and larger,” says Dr. Daniel Prime, Medical Research Associate at Medela. tubercles - the so-called glands of Montgomery. They secrete oil that moisturizes the nipples and will protect them from inflammation and infection when you start to feed. Scientists believe that the smell of this fat is similar to the smell of amniotic fluid and helps the newborn baby find the nipple.” ²

Do not use harsh soap for breast hygiene and do not rub hard with a towel as this can damage this natural lubricant. Just wash your breasts with warm water and pat dry. And if someone tells you to pinch or rub your nipples to prepare them for breastfeeding, don't listen to them!

If you have flat or inverted nipples, your pregnancy is over 32 weeks, and your pregnancy is normal, you can try inserting special nipple formers* into your bra in consultation with your doctor. They help to gently pull out the nipples so that it is easier for the newborn to grasp them. Consult your healthcare professional or read our article on flat and inverted nipples to learn more.

If breast size increases dramatically during pregnancy, breast skin may itch and stretch marks may appear on it. A good moisturizer can help soothe itching. The appearance of stretch marks usually depends on genetics and skin type. If you have a predisposition to stretch marks, it is unlikely that you will be able to prevent them, but, fortunately, over time they will become lighter and less noticeable.

Breast changes in the third trimester

In the last trimester, you may again experience soreness and heaviness in your chest. A sleep bra will keep you comfortable at night, while a supportive sports bra will help you avoid soreness and ligament damage during exercise.

Don't forget to buy a pair of nursing bras one month before your baby is born. If possible, consult a specialist in the store or study the online guide to select the appropriate model and size. Every woman is different, but usually cups of a nursing bra are chosen one or two sizes larger than before pregnancy. The underbust girth may also increase as the ribcage expands to provide enough room for the baby. The sales assistant should choose the size of your bra, taking into account the appearance of milk after childbirth. Models with fasteners that can be unfastened with one hand make it easier to attach the baby to the breast.

Surprising but true: milk appears in the breast even before the baby is born. This is why your nipples may start to produce some colostrum (the first breast milk), which will be quite thick and sticky. Sometimes this happens as early as 14 weeks, but more often it still happens in late pregnancy. To avoid the appearance of stains and smudges on clothes, you can use special bra pads.

“If you have diabetes or have been diagnosed with gestational diabetes, your doctor may tell you to express some colostrum by hand and freeze it. A recent study showed that after the 36th week it is quite safe if the pregnancy does not have other complications, ³ , says Dr. Prime, “Storing colostrum can come in very handy because babies with diabetic mothers are at higher risk of hypoglycemia (low blood sugar) and frequent colostrum feeding is the best remedy. . However, be prepared for the fact that there will be very little colostrum. You may only be able to express a few drops at first, and that’s perfectly fine.”

What happens to the breast after childbirth

Approximately two to four days after the baby is born (sometimes later if there was a caesarean section or a traumatic delivery), you will feel your breasts becoming heavier and firmer - this means that the milk has come. ⁴

“This breast fullness is not only due to excessive milk production – there is also an increase in the amount of blood circulating around the breast and the volume of lymphatic fluid,” explains Dr. Prime, “All this is the result of a gradual decrease in pregnancy hormone levels that began after the birth of a child and which allows the hormones responsible for the production of milk to enter into work.

During this period, you may experience soreness and discomfort in your breasts, a condition called breast swelling. This is quite common and usually resolves after a few days, during which time breastfeeding must continue. Read on for our tips on how to relieve swelling and discomfort, and if the problem persists, see a lactation consultant or healthcare provider.

What happens to the breast during lactation

For about the first three months of breastfeeding, your breasts are likely to fill up a lot before feeding. Over time, you may notice that your breasts become less full, but this does not mean at all that your milk production has decreased. If you are breastfeeding your baby exclusively and on demand, and at the same time he is growing well, then everything is in order with the amount of milk.

“Be prepared for the fact that after six months of breastfeeding, your breast size will begin to decrease,” Dr. Kent explains, “This is not a sign that your body is producing less milk. Most likely, the amount of adipose tissue in the breast simply decreased. By the time your baby is 15 months old, your breasts may be back to their pre-pregnancy size, but not smaller. However, whether you continue breastfeeding or not, you may still produce 100 to 300 ml of milk per day.”

This may be due to the start of more efficient milk production after six months of breastfeeding, which, according to Dr. Kent's research, may be the result of redistribution of breast tissue. ⁵

How your breasts change after you stop breastfeeding

When you finally stop breastfeeding—be it after three weeks, three months, or three years—the breast changes associated with lactation disappear. “After the complete cessation of breastfeeding, the breasts, as a rule, return to the size that they were before pregnancy. This usually happens in about three months, and for someone else while breastfeeding,” Dr. Kent explains, “If you get pregnant again, the whole process starts all over again. ”

Literature

1 Cox DB et al. Breast growth and the urinary excretion of lactose during human pregnancy and early lactation: endocrine relationship. Exp Physiol . 1999;84(2):421-434. - Cox D.B. et al., "Breast growth and urinary lactose excretion during pregnancy and lactation: an endocrine relationship." Exp Physiol. 1999;84(2):421-434.

2 Doucet S et al. The secretion of areolar (Montgomery’s) glands from lactating women elicits selective, unconditional responses in neonates.PLoS One . 2009;4(10): e 7579. - Doucet S. et al., "Papillary gland secretion (Montgomery's glands) in lactating women induces a selective unconditioned response in the newborn." PLOS One. 2009;4(10):e7579.

3 Forster DA et al. Advising women with diabetes in pregnancy to express breastmilk in late pregnancy (Diabetes and Antenatal Milk Expressing [DAME]): a multicentre, unblinded, randomized controlled trial. Lancet. 2017;389(10085):2204-2213. - Forster D.A. et al., "Women with Gestational Diabetes are Recommended to Express Milk Late in Pregnancy (Diabetes and Antenatal Pumping [ DAME ]): A Multicenter, Open, Randomized, Controlled Trial. Lancet (Lancet). 2017;389(10085):2204- 2213.

4 Infant and young child feeding: model chapter for textbooks for medical students and allied health professionals, Geneva : World Health Organization ; 2009. AVAILABLE FROM : https://www.ncbi.nlm.nih.gov/NBKS/NBK148965/ - "POSTICION" POSTICION "POSTRISS" POSTRIMENT "POST textbook for students of medical and related professions. Geneva: World Health Organization, 2009. Article cited: https://www.ncbi.nlm.nih.gov/books/NBK148965/

5 Kent JC et al. Breast volume and milk production during extended lactation in women. Exp Physiol. 1999;84(2):435-447. - Kent J.S. et al., "Amount and production of breast milk during long-term lactation in women". Ex Physiol. 1999;84(2):435-447.

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* RU № ФСЗ 2010/07352 of 07/19/2010

Breast changes during pregnancy

If you think that breasts grow only in youth, you are wrong! The complex internal structures needed to feed a baby only begin to form during pregnancy, and until recently we didn't even know how it happened.

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Did you think about your breasts during pregnancy? Surely only in the context of buying a special bra. Meanwhile, at this time, huge changes take place in the chest. Not only the uterus, but also the breast undergoes an amazing transformation to prepare for the birth of the baby. But to understand, let's go back a little...

Breast development during adolescence

The breast changes continuously from adolescence until menopause. Unlike other organs, it does not grow until it is "activated" by hormones produced during puberty. However, even when the breast appears to be fully developed, it is not yet mature.

“After the completion of puberty, the female breast continues to develop. With each cycle, the amount of secretory [milk-producing] tissue increases slightly, and this continues until about 35 years old,” says Professor Peter Hartmann from the University of Western Australia, an expert in lactation, “After reaching this age, breast development stops, it becomes mature , but remains "sleeping" for the time being.

During the menstrual cycle, the cells of the breasts are renewed, which can make them more sensitive, painful or swollen. ¹

You may have noticed that at the beginning of the cycle, the breasts are somewhat lumpy to the touch. During this period, preparation for a possible pregnancy takes place. If pregnancy does not occur, a new cycle of falling and rising hormone levels begins. ²

Internal breast changes during pregnancy

When conception occurs, the cycle is interrupted. From the end of the first month of pregnancy, the breast begins to gradually turn into a milk-producing organ.

At this time, the number and branching of the milk ducts increase and an extremely complex feeding system is formed. At the same time, cells called lactocytes begin to develop in the breast, which produce milk. The amount of blood going to the breast doubles during pregnancy. That is why the veins sometimes shine through the skin. ³

"After the birth of the placenta, the level of progesterone begins to fall and the process of lactation starts"

“When pregnancy occurs, the breast literally turns on,” says Professor Hartmann. “After conception, the secretory tissue of the breast begins to grow. There are clusters of tubercle-like glands in the breasts, and when pregnancy occurs, these tubercles begin to grow and form ducts and tiny sacs, called alveoli, that will store the milk.”

All of these processes in the breast can cause sensations of heaviness, soreness and swelling, which are early signs of pregnancy. Read more in the article about how breasts change during pregnancy.

Structure of the lactating breast

Believe it or not, scientists have only recently discovered how the complex system of ducts located in the breast works.

Until the beginning of this century, most medical knowledge about milk production was based on experiments conducted by the English surgeon, Sir Astley Cooper, in the 1840s. ⁴ He concluded that milk is stored in the ducts and exits through 15 to 20 orifices in the nipple. Professor Hartmann's colleague, Dr. Donna Geddes, along with a team of scientists backed by Medela, discovered that breasts function very differently. ⁵ The ducts are indeed small tubes only a few millimeters in diameter, but they serve to transport the milk, not to store it. Milk is produced and stored in the alveoli. These sacs are connected to the ducts by even smaller tubes called tubules. ⁶

The milk stays in these sacs until the hormone oxytocin is produced in the body, which happens when the baby starts suckling. The alveoli are surrounded by muscle cells that contract under the influence of oxytocin, and these contractions move the milk through the ducts to the nipple. This process is called the milk flush reflex. Sometimes it can be felt as a tingling or slight movement that occurs in the breast when you start to feed the baby, but some women do not feel it at all. ⁷

Dr. Geddes and colleagues also found that there are fewer holes in the nipples than previously thought: usually around nine, sometimes as few as four. The ducts have to expand by almost 68% to accommodate the entire volume of milk flowing rapidly to these several outlets. ⁸

“Throughout breastfeeding, the structure and function of the breasts remain virtually unchanged until the baby begins to consume less milk,” explains Prof. Hartmann.

The breast begins to produce milk during pregnancy

From about the middle of pregnancy, the alveoli are already capable of producing milk. Fortunately, pregnancy hormones limit the production, ⁹ otherwise, by the time of delivery, the breast would simply burst.

“Producing 800 ml of milk a day during pregnancy is absolutely useless,” notes Professor Hartmann. “Therefore, the level of progesterone in the body rises, which prevents the activation of production. However, after the birth of the placenta, the level of progesterone begins to fall rapidly and the process of lactation starts.”

What happens to your breasts when you stop breastfeeding? She goes into a state of rest, but not immediately. “When a woman completely stops breastfeeding, it takes some more time – usually a month or two – for milk production to completely stop,” explains Professor Hartmann, “In humans, the process of stopping milk production takes a long time, although in other mammals this happens pretty fast. "

The breasts eventually return to their pre-pregnancy state. If you become pregnant again, the same cycle of growth and development will begin all over again. ¹

Would you like to know more? Download the free e-book Surprising Breast Milk Facts or read our article Why Colostrum Is So Important?.

Literature

1 Hassiotou F, Geddes D. Anatomy of the human mammary gland: Current status of knowledge. Clin Anat . 2013;26(1):29-48. - Hassiot F., Geddes D., "The structure of the female breast: what we know today." Wedge Anat. (Clinical Anatomy) 2013;26(1):29-48.