Pregnanediol is an inactive product that forms when the body breaks down the hormone progesterone. A test can be done to measure the amount of pregnanediol in urine. The urine test offers an indirect way to measure progesterone levels in the body.

Before progesterone blood tests were available, this test was used to monitor pregnancies and check for possible problems with the ovaries or adrenal cortex.

In women, progesterone is produced mainly after the ovaries release an egg (ovulation). The main function of progesterone is to help the uterus prepare for possible implantation of a fertilized egg. After fertilization, progesterone is necessary for the development of the placenta, the organ that develops to nourish the growing baby. During pregnancy, most progesterone is produced by the placenta.

Some progesterone is also produced by the adrenal cortex. See: Adrenal glands

Currently there is little use for this test except in home ovulation predictor kits.

A 24-hour urine sample is needed.

Your doctor may tell you to stop taking certain drugs that can affect the test. For example, ACTH may increase test measurements. Birth control pills or progesterone may decrease test measurements.

The test involves only normal urination, and there is no discomfort.