The London Clinic provides a full breast care service for women who are worried about their breast health or who have developed breast cancer. View our Breast services. Please see our Privacy Notice for further details on how we use your personal data. Breast development starts in an unborn baby and is completed during puberty and pregnancy. It is completely normal for women to have one breast that is slightly different from the other. One may be larger, a different shape or in a slightly different position. Usually, the difference is not outwardly noticeable to anyone other than the woman herself, but there are some more obvious problems with breast development that can cause significant psychological distress and physical problems, prompting those affected to seek medical help and advice.

When does breast development begin?
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We include products we think are useful for our readers. If you buy through links on this page, we may earn a small commission. These stages will be different as well for those undergoing gender transition. The size of the breasts will also vary a lot from one person to another. Yes, breasts can hurt when they grow.
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Lots of girls and guys worry about when their bodies will develop. Guys wonder when their voices will get deeper, when they'll need to shave, or when their penises will grow. Girls want to know when their breasts will develop or when they'll get their first period. If a friend or a younger brother or sister develops first, they may worry that there's something wrong with them. The fact is that physical development starts at different times and progresses at different rates in different people. So, the beginning of the development that comes with puberty varies from person to person — and that's completely normal. The earliest physical change of puberty for girls is usually breast development, which most often begins around 10 or 11 years. But it's perfectly normal for breast development to start anytime between the ages of 7 and
Breast development is a vital part of puberty in females. It occurs in stages: first before birth, then during puberty, and then again during the childbearing years. Changes also occur to the breasts during menstruation and when a woman reaches menopause. This is when a thickening in the chest area called the mammary ridge or milk line develops. By the time a baby girl is born, nipples and the start of the milk-duct system have formed. The first thing to develop are lobes, or small subdivisions of breast tissue.