Women's Corner
Women's Corner
Early childhood : Low levels of GnRH , gonadotropins and estrogen
· The Gonadostat is 6-15 times more sensitive to the negative feedback .
· Intrinsic CNS inhibitor .
Late childhood (prepuberty) :
· Release of the inhibition of the gonadostat (decreased suppression) : be due to
- Decreased sensitivity of the hypothlamo-pituitary receptors to low estrogen levels
- Release of the inhibitory effect of the CNS intrinsic factor
- Reduction of melatonin (doubtful)
· Gonadarche : As a result of release of the gonadostat from inhibition , the GnRH starts to increase first at night leading to mid-night pulses of LH and moderate rise of FSH which stimulates release of estradiol .
· Adrenarche : Pituitary adrenal-androgen-stimulating factor (from preopio-melano-cortin) stimulates the adrenal gland to produce DHA, DHAS and androstenedione .
Puberty : The sequence observed includes :
1. Pulsatile pattern of LH release that gradually extends through-out the day to occur at roughly 1.5-2 hours intervals
2. Episodic peaks of estradiol secretion leading to menarche
3. By mid to late puberty , maturation of the positive feedback relation between the estradiol and LH occurs leading to puberty .
- Frisch thesis : A crtical weight (96 lb) and a critical % of body fat (22%) menarche
- Stages of development :
1. Spurt of growth
2. Thelarche: due to fat deposition and duct system development. Median age is 9.8 years
3. Adrenarche .
4. Menarche : Median age is 12.8 years .
dr. Hisham Al-Inany Lecturer in Obstetrics and Gynecology Department, Cairo University, Egypt Dr. Amr Hussein Lecturer in Obstetrics and Gynecology Department, Cairo University, Egypt