DEAR DOCTOR, My daughter will be 15 this year but she is yet to grow breasts. She only got her first menstrual period last year and it is irregular. Is this normal? Should I be worried? NOELLA DEAR NOELLA, Puberty begins in girls by the age of eight or nine, or even later, to 17 or 18 years. It is signalled by development of breasts and appearance of pubic hair. Early signs of breast development is feeling of spongy or rubbery lump below nipple. The nipples may feel sore or painful to touch. Puberty occurs due to surge in level of oestrogen and balance between oestrogen and progesterone. This hormonal change varies from one individual to another, depending on genetic and lifestyle factors. One may have early or late development of breasts, if the mother or any aunt or a close female relative has had an early or delayed development of breasts, the individual girl may have the same. High fat and or high protein diet can cause early breast development, as breasts are made of fatty tissue only. Vice versa is also true. Breast size and development also depends on level of nutrition. A woman may have small breasts since puberty, but if she gains weight after puberty, her breast size also increases. In case of low calorie diet, breast development can be affected and even delayed. Breast development is also affected by hormonal disorders, like that of thyroid, pituitary and adrenal glands. Drugs like steroids, hormone supplements, can affect breast development as well. There is nothing to worry or panic about, if breast development is delayed. You can wait till your daughter is 17, 18 or even 20 years old. If she is growing well in other parameters, is intelligent, active and adaptive as per her age, there is no need to worry. Menstrual cycles also start due to surge in and balance between levels of oestrogen and progesterone. Initially menstrual cycles are irregular, till about 6 to 12 months, after this time, usually a fixed pattern is established, where commonly menstrual periods occur after 28 to 30 days, plus, minus one week. Hence, there is no need to become anxious over irregular periods at just 15 years of age. You can wait up to three or four years from now. Hormonal disorders, use of certain drugs, can delay onset of regular menstrual periods. If the onset of regular menstrual periods does not occur by 17 years, get her investigated for hormonal disorders like polycystic ovarian syndrome, thyroid, pituitary or adrenal disorders. All these are treatable. Dr. Rachna Pande is a specialist in internal medicine rachna212002@yahoo.co.uk