What is progesterone?

Progesterone is a female steroid hormone that is produced by the corpus luteum, which is the placenta. This process appears during pregnancy and near the adrenal cortex. In pregnancy progesterone acts in such a way that it protects the embryo and fosters the growth of the placenta. By decreasing the number of uterine contractions it aids in the prevention of expulsion of the implanted zygote. It also promotes secretory changes in the mucosa of the fallopian tubes, hence helping to provide nutrition for the fertilized ovum as it travels through the tube on its way to the uterus. Progesterone in males, contributes to the synthesis of other steroid hormones.

Progesterone in women, increases the process of ovulation and decreases it before menstruation, pregnancy increases progressively, which allows the thickening of the endometrium to provide nutrients to the fetus, reducing the contractions of the uterus. Another important function of progesterone is promotion of the development of the mammary glands in preparation for lactation. Prolactin from the anterior lobe of the pituitary gland, stimulates production of milk, and progesterone prepares the glands for milk secretion. Progesterone also has an indirect effect on the fluid and electrolyte balance of the body by blocking the effect of aldosterone. Diminished secretion of progesterone can lead to menstrual difficulties in women who are not pregnant and spontaneous abortion in pregnant women.

Why measure the level of progesterone?

In women of childbearing age it is a good indicator of the health of the menstrual cycle. Progesterone is used medically in the treatment of dysfunctional uterine bleeding and abnormalities of the menstrual cycle, as part of postmenopausal hormone replacement therapy, as a test for endogenous estrogen production, and as an adjunct in the treatment of infertility associated with partial or complete ovarian failure. It is administered orally, intramuscularly, or intravaginally. It also helps to track ovulation, which increases progressively during pregnancy and indicates the growth of the fetus.

Progesterone is included along with estrogen in combination oral contraceptives and in menopausal hormone therapy. Progestins are also used alone for birth control and for treatment of a variety of other conditions, including abnormal uterine bleeding and amenorrhea (absence of periods); endometriosis; breast, kidney or uterine cancer; and loss of appetite and weight related to AIDS and cancer. Progestins may also be used as a diagnostic aid to check the effects of estrogen.

Standard of preparation

Sampling is usually done in the morning in the hospital. There are no special preparations needed for this test. The doctor will advise and recommend if you need to be fasting prior to the blood examination. You should inform your doctor of any medication you are taking prior to the exam, as some medical treatments may interfere with the blood results.

Is the examination painful or dangerous?

The examination is neither painful nor dangerous. The patient may feel a tingling sensation with the entrance of the needle in the arm when blood is being extracted for examination.

How is the exam performed?

The exam consists of a simple blood sample test.