Ovaries

About the Ovaries

The ovaries are paired almond shaped organs approximately 3 cm long on either side of the uterus. They produce ova eggs and hormones estrogen, progesterone, inhibin, and small amounts of testosterone. At birth, a female has approximately 1 to 2 million primordial follicles, declining to 300,000 to 400,000 at puberty, of which approximately 400 will ovulate. The ovarian cycle has follicular phase FSH stimulating follicle growth, ovulation LH surge releasing the oocyte, and luteal phase corpus luteum producing progesterone. Menopause at approximately age 51 occurs when follicles are depleted. Estrogen causes female secondary sexual characteristics and endometrial proliferation. Progesterone maintains the uterine lining for pregnancy. Polycystic ovary syndrome PCOS involves excess androgens and anovulation.