Breast development age in girls can differ widely. However, on an average, the development of breast commences somewhere between the ages of 10-15. The first indication announcing the formation of breasts is a tender, yet firm lump under the areola of one or both breasts. This soft lump is known as Thelarche and this stage of breast development is called the Tanner Stage 2, Tanner Stage 1 being the absolutely undeveloped stage just preceding the formation of the Thelarche. Thelarche are also nicknamed as “breast buds” as they precede the full bloom of the female physical flora! The formation of the thelarche is a result of a rise in Estradiol levels in the female body during puberty. Estradiol is the most significant sex hormone in females and it’s role is to regulate the growth of the reproductive organ tissues besides taking care of the vaginal lining, cervical glands, endometrium and the lining of the fallopian tubes.
Within six to twelve months of the formation of the thelarche, the area around both areolae begin swelling up, extending beyond their edges. This mound is soft to the touch and very sensitive in the beginning, sometimes hurting slightly. Within another twelve months, the breasts grow to their full size and you can see the areola and the mammary papillae forming a second, very small mound on the main breast mound. These secondary mounds are what we call nipples. The nipples and the surrounding areolar patch is distinguished by darker pigmentation than the rest of the breast. The nipples contain very small outlets for around 15-20 lactiferous ducts which carry milk that form inside the mammary glands during pregnancy. While breastfeeding, these tiny perforations in the nipples enable the milk from the mammary glands, carried by the lactiferous ducts, to reach the infant’s suckling mouth.
Other Physical Changes During Puberty
During the onset of puberty, besides breast development, girls undergo many other visible physical changes such as a change in their body shape and body fat distribution. The hip and pelvic regions widen and the fat distribution in certain areas of the body such as breasts, hips, thighs, buttocks, upper arms, etc., increase to give the average female body that “curvy” shape. Also, during this period, girls develop hair on their armpits and pubic region. Increased estrogen levels at this stage leads to changes in the mucosal surface of the vagina and growth in the size of ovaries, uterus and ovular follicles. Young people between puberty and adulthood are called adolescents and this in-between-time is needed by the body to adjust to the drastic changes brought on by puberty.
Menstrual bleeding (what we commonly know as periods or “chums”) typically starts about two years after the formation of the thelarche. This is the ovulation cycle and is necessary for female fertility. In the beginning the periods are pretty irregular as the body is still adjusting to the sudden changes. The first menstrual period is known as menarche.