Many women wonder if their breasts will get bigger over time. Breast size is influenced by a variety of factors including age, weight fluctuations, pregnancy, and hormone levels. While breast size can increase during certain periods of a woman’s life, there are also times when breasts may get smaller. Understanding the typical changes that occur can help women know what to expect as they go through different life stages.
Key Factors That Influence Breast Size
There are several key factors that impact breast size in women:
Age
As girls go through puberty, rising estrogen levels will cause breast tissue to start developing. It is common for breast buds to first appear between the ages of 8-13. Breast growth will continue throughout puberty until reaching full adult size. Breasts will change the most during the teen years and early 20s.
By the late teens and early 20s, estrogen levels drop off and breast tissue finishes developing. At this point, breast size typically stabilizes. However, breast size can fluctuate slightly throughout the remainder of the reproductive years based on weight, hormonal shifts, and other factors.
During menopause, declining estrogen may cause breasts to get smaller and feel softer as breast tissue starts to get replaced by fat.
Weight Changes
Breast size is heavily influenced by the amount of adipose (fatty) tissue in the breasts versus milk gland tissue. When weight goes up, the increase in body fat often leads to larger breast size. Losing weight can result in the breasts reducing in size. However, weight loss impacts every woman differently. For some women, the breasts remain nearly the same size after losing weight due to genetic factors.
Pregnancy and Breastfeeding
Hormonal changes during pregnancy prepare the breasts for lactation. Estrogen, progesterone, prolactin, and other hormones cause the milk ducts and milk glands (lobules) to enlarge. This expansion of breast tissue leads to increase in cup size during pregnancy for most women.
After pregnancy is over, the breasts will decrease in size again. However, it is common for the breasts not to return completely to their pre-pregnancy size especially after multiple pregnancies. Some women go up 1-2 bra sizes permanently after having children.
Breastfeeding keeps prolactin levels elevated which maintains milk production. For some women, breastfeeding makes the breasts larger than they were during pregnancy. Once breastfeeding ends, prolactin levels drop and the breasts will gradually return to their post-pregnancy size.
Hormonal Contraceptives
Birth control pills, implants, shots, and other hormonal contraceptives all contain estrogen. The estrogen can cause fluid retention and growth of breast tissue, leading to increase in breast size. For some women, going off hormonal birth control can result in the breasts shrinking back down partially. However, breasts may not return to their exact pre-pill size.
Menstrual Cycle
Hormone levels fluctuate throughout the menstrual cycle each month. Estrogen is lower during menstruation and higher mid-cycle around ovulation. The changing hormone levels can cause breasts to temporarily swell and feel full/tender at certain points in the cycle. Monthly breast changes are typically minimal. However, some women experience more noticeable enlargement mid-cycle or before menstruation.
Common Times Breasts Get Bigger
Based on the factors that influence breast size, there are certain life stages when women are most likely to see their cup size increase:
Puberty
The most dramatic breast growth occurs during puberty. As girls go through puberty, it is extremely common for breasts to increase several bra sizes over 2-4 years. The amount and speed of growth varies based on when puberty starts and each girl’s unique genes/hormones. Most of pubertal breast development happens between the ages of 10-14. However, breasts can continue expanding into the late teens/early 20s before reaching full maturity.
Pregnancy
Pregnancy causes significant breast enlargement due to hormonal influences on breast tissue. Most women will go up 1-3 cup sizes over the 9 months of pregnancy as the milk glands prepare for lactation. Breast size starts expanding right from the early stages of pregnancy for many women. The most rapid growth often occurs between 16-22 weeks of pregnancy.
Weight Gain
Putting on a significant amount of weight can increase breast size at any age after puberty. During weight gain, extra fat tissue accumulates in the breasts. How quickly and how much breasts enlarge from weight gain depends on the individual. Genetics play a role in where women store excess fat. For those predisposed to store fat in their breasts, even a moderate weight gain of 10-20 pounds can increase cup size.
Going on Birth Control
Within the first few months of starting hormonal contraceptives like the pill, implants, or shots, many women notice their breasts feeling fuller and larger. The estrogen in hormonal birth control leads to fluid retention that enlarges breast tissue. Breasts may get up to 1 cup size bigger from birth control methods. However, the breasts will often return to their former size after stopping the hormones.
Mid-to-late menstrual cycle
Breasts can feel swollen and appear slightly larger around ovulation as estrogen spikes mid-cycle. Right before getting a period, some women also retain fluid and experience breast enlargement premenstrually. These cyclical size changes are typically subtle, but can be more pronounced in some women. The breasts go back to normal smaller size following onset of menstruation.
During breastfeeding
After giving birth, breast changes continue as the milk supply comes in. Breastfeeding keeps prolactin levels high which maintains production of breast milk. Many women find their cup size increases even more while nursing compared to during pregnancy. Once breastfeeding ends, the breasts will gradually decrease to post-pregnancy size over 3-6 months.
Common Times Breasts Get Smaller
Just as breast size can increase during certain periods of life, there are also times when women may notice their breasts getting smaller:
Menopause
As women go through menopause, diminishing estrogen causes changes in breast tissue. The milk glands and connective tissue start to break down and be replaced by fat. This transition typically leads to loss of volume, sagging, and breasts feeling softer/less firm. Actual cup size may go down 1-2 sizes for some women from menopausal breast atrophy.
Weight loss
Losing a significant amount of weight causes the breasts to shrink for most women. Each woman loses weight differently based on genetics, which impacts how much breast size decreases. For substantial weight losses of 40+ pounds, it is common to go down 2+ bra sizes from loss of fat tissue in the breasts. However, pregnancy/nursing history also play a role in how much breast tissue remains after weight loss.
Stopping hormonal contraceptives
When women stop taking hormonal birth control like the pill, implants, or shots, the drop in external hormones can lead to fluid loss from breast tissue. Some women do go back down about 1 cup size after discontinuing hormonal contraceptives. But for others, their breasts remain about the same size or only get slightly smaller. Genetics, age, and weight changes all affect size after going off birth control.
During menstruation
Some women experience swelling and fullness in the breasts mid-cycle as estrogen rises. When estrogen drops off during menstruation, this cyclical breast enlargement goes away. Monthly reductions in breast size during menstruation are subtle for most women. But a small subset do routinely notice their breasts feeling/looking smaller when getting their period.
After weaning from breastfeeding
Breast size remains increased for the duration of breastfeeding to accommodate milk production. Around 3-6 months after fully weaning, most women will drop back down close to their post-pregnancy breast size as the milk glands shrink. The breasts will gradually become smaller and less firm after breastfeeding stops.
After pregnancy
While breasts expand during pregnancy, most women find their breasts get smaller again in the months following childbirth. Over the first 6-8 weeks postpartum, the milk glands and breast tissue that enlarged during pregnancy will start to regress. The breasts typically deflate and decrease in cup size as they return to non-pregnant proportions. However, it is common for breasts not to fully return to pre-pregnancy size after babies, especially with multiple pregnancies.
Breast Size FAQs
Here are answers to some frequently asked questions about breast size changes:
Do breasts keep growing into your 20s?
Breast development starts during puberty and continues into the late teens and early 20s. Most of the growing is complete by ages 17-18. However, breasts can continue expanding slightly into the early 20s before final adult size is reached. It is common for cup size to increase by 1 size between ages 18-22. But significant growth years after puberty is uncommon unless weight gain occurs.
At what age do breasts stop growing?
There is no definitive age when breast growth stops. The end of breast development depends partially on when puberty starts. On average most breast development tapers off around ages 17-19. But some women may experience slight increases in breast size into their mid-20s due to genetics and continued hormonal maturation. After the 20s, breast size typically remains stable except for temporary changes related to menstruation, pregnancy/nursing, menopause, etc.
Do breasts grow during ovulation?
Some temporary enlargement of the breasts around ovulation is normal. The natural rise in estrogen mid-cycle can cause fluid retention in breast tissue, making them feel fuller/swollen. Breasts may appear slightly larger for some women during ovulation. But the size increase is usually subtle, in the range of 1/4 to 1/2 cup at most. After ovulation, breasts return to their normal size.
At what age do your breasts stop growing during puberty?
There is a wide range in the age at which breast growth completes, but final development usually happens somewhere between ages 15-18. Girls who start puberty early will finish breast development sooner, often by age 15 or 16. Later maturing girls may see breasts continue expanding into their late teens or even early 20s before reaching full size. Most girls will be done with the majority of breast growth by age 17 or 18 after starting puberty between ages 8-12.
Can breast size decrease permanently?
In some cases, yes – there are life events that can cause breasts to shrink permanently. Pregnancy/nursing enlarges the milk glands. After weaning, these glands shrink leaving the breasts smaller. Significant weight loss also reduces fat tissue in the breasts that does not always return if the weight is kept off. Aging and dropping estrogen levels during menopause leads to loss of glandular tissue over time. Since glandular tissue does not regrow, these reductions in breast size due to pregnancy, weight loss, and aging can be permanent.
Do breasts shrink after pregnancy?
It is very common for breast size to decrease after pregnancy. During pregnancy, rising hormones like estrogen, progesterone, and prolactin cause the milk ducts and glands to grow – enlarging the breasts. In the first 6-12 weeks after giving birth, most women experience breast deflation as the enlarged milk glands shrink back down. The breasts are likely not to return fully to pre-pregnancy size, but will be smaller than they were during pregnancy. Multiple pregnancies can result in more glandular tissue development, leaving breasts permanently larger.
Conclusion
Breast size is influenced by a woman’s age, weight fluctuations, hormones, and major life events like pregnancy. Typical times breasts get bigger are during puberty, pregnancy, weight gain, and for some women – while taking birth control pills. Common times for breasts to shrink are after pregnancy, menopause, weight loss, and weaning from breastfeeding. While breasts can change sizes during different life stages, genetics play a key role. Understanding the factors involved can help women know what to expect with their unique bodies over the lifespan.