Did You Know?

When a woman is born she is born with all of her reproductive material.  That means she is born with all of her eggs (unlike men who do not start to produce sperm until puberty and continue to do so for their entire lives), the eggs are stored in the ovaries. The ovaries are a housing unit, the hormones we make are made by the eggs inside the ovaries, not the ovaries themselves.  

 Women are born with about 1 million eggs.  By the time a woman is in her 30’s, she is down to about 100,000-200,000 eggs. By the time a woman is 40 she has approximately 10,000 - 30,000 eggs, and by the time she is 50 she has around 1,000 eggs left.  

When we are most fertile, ages 20- early 30’s  our body prepares 500-1000 eggs to ovulate a month.  Most do not make it, some die, while others never totally mature.  We ovulate 1 egg a month (sometimes 2). The lucky one who matures and finds its  way from the ovary to the fallopian tube has the opportunity to get fertilized.  If the egg is not fertilized we experience a period. 

During our reproductive era and with ovulation, our hormones estrogen and progesterone rise and fall in a very predictable pattern, because we have an abundance of eggs to produce the levels of  hormones that the body needs for normal function.  But as we age the egg supply diminishes and the eggs themselves are becoming older and less effective at producing the hormones needed  affecting the estrogen, progesterone and testosterone levels. 

During the perimenopausal time of  life our egg supply is quickly diminishing and the pattern of ovulation becomes chaotic, the normal up and down pattern is more erratic and unpredictable.  A woman may experience skipping periods, heavier periods, lighter periods or longer intervals between periods.  The amount of eggs influences the amount of estrogen and the amount of estrogen influences eggs ovulation.  There is little of both.  Progesterone, because it is estrogen’s partner, also decreases due to the same process and follows the same chaotic pattern, so we may experience more moodiness, irritability, and trouble sleeping.   Progesterone starts to decline before estrogen does, usually beginning in our 30’s.  Once we stop having periods and are post menopausal our estrogen and progesterone levels are at the lowest point and will not return on its own.  Testosterone is a little different. Some of our testosterone is produced by the eggs in our ovaries, but production remains via the adrenal glands.  Our testosterone levels start to decline in our late 20’s but we never run totally out of it, like we do estradiol and progesterone.