Ovarian Physiology

At birth, women are born with some 7 million eggs. These eggs lie immature within the ovaries until puberty is reached with the vast majority of them being reabsorbed by the body throughout chilhood. At puberty, a woman will have approximately 300,000 eggs available for future ovulations with most of the eggs continuing to be reabsorbed as a woman ages. A woman ovulates approximately 400 times during her life.

If the ovary released one egg per cycle each month, a woman would have thousands of years to use up all of her eggs. Instead, each month several dozen to several hundred immature eggs leave their resting state and resume growth. Typically one egg fully matures and is able to ovulate. The remaining eggs are reabsorbed by the body and never used.

Two hormones control the maturation and release of one egg from several hundred. They're called Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH). Both hormones are produced in the pituitary gland. FSH stimulates the initial growth of the many egg-filled structures known as follicles. Follicles are a combination of an egg and surrounding cells. They provide for the egg's development. As follicles begin to grow in response to FSH, they begin producing their own hormone called estrogen.

Estrogen levels in the blood stream are detected by the pituitary gland. When levels are low, FSH production is increased to stimulate further development of the follicles. As estrogen levels rise in response to the increasing levels of FSH, the pituitary gland responds by releasing less and less FSH. The body tries to keep circulating FSH at the lowest possible level, so it can still sustain the growth of one dominant follicle. This is done so only one mature egg will be released each month.

Contact the Gyft Clinic for affordable fertility and gynecology services. Schedule an appointment at 253-777-1964.