Hormonal Causes of Abnormal Uterine Bleeding

Hormones are chemical messengers between the cells of the body. There are many kinds of hormones from various glands in the body, and many of them influence the menstrual cycle. 

Below are only a few of the major hormones needed for our bodies to function. Complicating things further is the fact that they all interrelate and influence each other. Between the number of hormones in play and the influences they have on one another, it is difficult to understand how they affect bleeding. 

Pituitary hormones:

Growth hormone (GH) , Follicle stimulating hormone (FSH) , Lutenizing hormone(LH), Prolactin (PRL) , oxytocin (aka pitocin)

These are directly or indirectly related to growth and reproduction. 

Adrenal hormones:

epinephrine, norepinephrine, etc.,  which help us with fight or flight response

cortisol, which releases glucose for energy and suppresses inflammation

Thyroid hormones:

Govern metabolism and are related to ovulation 

Sex steroid hormones:

testosterone, estrogen and progesterone, which are directly involved with reproduction 

The workup  for hormonal causes of abnormal bleeding

A workup is the series of tests and procedures which is done to determine the cause of something. The workup for abnormal uterine bleeding will probably involve checking some of your hormones, but not the ones you might think. We rarely check estrogen and progesterone levels. That is because they are constantly changing over the course of hours, days, weeks and months. One snapshot in time of their values tells us very little. When we do check hormone levels, we do so with a blood sample. Saliva samples are not considered useful. 

Various hormone abnormalities cause problems with the period. Common blood values to check include TSH (thyroid stimulating hormone), PRL (prolactin), and FSH (follicle stimulating hormone). We can also assess hormone status by doing a provocative test. This means we give a medication, like a progesterone, to see if it brings on a period. If it does, this tells us the endometrium is estrogenized. 

One common reason for AUB is failure to ovulate. Failure to ovulate produces an abnormal hormonal condition which produces abnormal bleeding. This is because the normal cycle of ovulation results in the production of estrogen and later the production of progesterone. These hormones act in sequence on the endometrium (lining of the uterus) resulting in the production of the normal menstrual flow. If there is no ovulation, the normal sequence of hormones does not occur, and the bleeding becomes abnormal. This is such an important category of problem that it deserves its own section: 

Please see Chronic Estrogenized Anovluation.