Puberty is the period which links childhood to adulthood, which is at 12–14 years of age and is characterized by increased body growth. Puberty leads to fully maturation with various biological and psychological changes. It is brought about by the start of the ovarian activity and production of hormones.

Before puberty begins, the anterior pituitary produces growth and other tropic hormones and does not produce gonadotrophins. The ovaries are not active. At puberty, production of the gonadotrophins starts due to increased activity of the anterior pituitary. Maturation takes place and primordial follicles is changed into graafian follicles. The graafian follicles produce estrogens. The body undergoes various changes due to the hormones which are mainly seen in the breast, pubic and axillary hair growth, commencement of menstruation, growth in height and general metabolism of the body.

Development of the Secondary Sexual Characters
The secondary sexual characters develop in the following order

• Pubic and Axillary hair
  The growth of hair on the mons veneris and in the axillae starts at puberty.
• Pelvis
  It becomes wide.

Menarche
The menarche occurs at puberty. The ovarian hormones, estrogens and progesterone, act on the endometrium. The endometrium becomes thick, and is shed cyclically on withdrawal of these hormones.

Skin Changes

• Acne.
• Acne spots appear on the face which may be due to estrogens.
• Pigmentation.
• There is increased pigmentation of the body skin, may be due to increased production of melanin stimulating hormone.

Growth of the Genital Tract
The genital tract, under the influence of ovarian hormones, grows and increases in size.

• Ovaries
  They change their shape and becomes elongated. They become bulky and oval.
• Uterus
  The body of the uterus increases in size and changes form the immature type to the adult type.
• Vagina
  The changes are seen more over here. The vaginal epithelium increases in thickness due to storage of glycogen in its superficial and intermediate zones. Doderlein’s bacilli appear in the vagina, and its pH becomes acidic. The labia majora become more prominent due to deposition of subcutaneous fat. The vulva becomes more reactive. The mons pubis and labia minora increases in size.

Psychological Changes
At puberty, girls become more shy, reserved, and blush easily. They also become sensitive and at times moody.

Delayed Puberty
Puberty may be delayed when breast tissues or pubic hair have not appeared by 13–14 years and menarche is late and appears by the age of 17 to 18 years. Generally there is a family history of delayed menarche. In some cases the delay may be because of environmental influence on the hypothalamus, or due to some endocrinal or systemic insufficiency. Usually, in a case of delayed menarche, the menstruation is irregular and infrequent. The girl may have prolonged periods of amenorrhea or sparse menstrual flow. These women do not need any treatment. Only reassurance and follow up is enough in a most of these cases.

Precocious Puberty
This is early onset of puberty. In this, the girl exhibits secondary sex characters at the age of 8 years or start menstruation at the age of 10 years. It may happen as early as 2nd or 3rd year of life. The physical growth is usually stunted due to early closure of epiphyses. In a majority of these cases no cause is found. There is no organic lesion seen.
The following lesions may cause precocious puberty:

• Meningitis.
• Encephalitis.
• Cerebral tumor.
• Feminizing ovarian tumors like.
• granulosa cell tumor.
• theca cell tumor.