Progesterone Challenge Test Dosage, Side effects, Physiology and Results

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Progesterone Challenge Test (or Progestogen Challenge Test or Progestin Challenge Test PCT or Progesterone Withdrawal Test) is a test that is done to help in the diagnosis of Amenorrhea; this test was used before the development of other assays used in the measurement of serum levels of estradiol. The Progestogen Challenge Test was used to check for the effect of Progesterone on the inner layer of the uterus (Endometrium). Progesterone usually induces endometrial bleeding after withdrawal but this happens only when the circulating level of serum estradiol is at least 50pg/ml.

Progesterone Challenge Test Procedure

  1. Administer intramuscular injection of progesterone (100-200mg intramuscularly as a single dose) or oral progestogen for 5 days (Medroxyprogesterone acetate this is commonly called Provera).
  2. Within an average of 3 days (range of 10-14 days) of stopping the administration of the progesterone, there should be a withdrawal bleed.
  3. If there is bleeding, it means that the endometrium has been primed with estrogen and that the uterus is present and that there is no outflow tract obstruction. This shows the amenorrhea is caused by anovulation.
  4. If there is no bleeding, it means there is either no uterus or there is obstruction to flow of blood

Progesterone Challenge Test Dosage

  1. The dose of Progesterone given in the progestin challenge test is 10 mg of Medroxyprogesterone acetate, given daily for 5 days.
  2. If the progesterone challenge test is negative, then when giving the estrogen and progesterone therapy; the dosage are 1.25 mg of conjugated estrogens given for 21 days, with the addition of a progesterone for the last 5 days.

Progesterone Challenge Test Uses

  1. Progesterone causes endometrial bleeding after withdrawal in the presence of enough estradiol and for this occur, it shows the uterus is present. The Progesterone Challenge Test therefore shows whether the uterus is present or not as there are congenital anomalies with absent uterus.
  2. When bleeding occurs after Progesterone Challenge Test, it shows there is a patent reproductive tract for the blood to flow out. This helps to rule out outflow tract causes of amenorrhea.

Negative Progesterone Challenge Test Result (No Period after Progesterone challenge test)

  1. A negative Progesterone Challenge Test shows there may be low serum levels of estrogen in the body
  2. There may be obstruction to the flow of blood such as in Ashermans syndrome (there is adherence of the endometrial walls together) or imperforate hymen or cervical stenosis
  3. There may be a non-reactive endometrium or there may be no uterus (absence of uterus due to congenital abnormalities)

How to distinguish outflow tract obstruction with low serum estrogen when you have a Negative Progesterone Challenge Test

When there is a negative Progesterone Challenge Test and you want to know if the lack of bleeding is due to obstruction of the outflow tract or it is due to low serum estrogen; all you need to do is to administer estrogen and then do another Progesterone Challenge Test, if bleeding occurs after administration of estrogen, then the negative test was because of low serum estrogen but if there is still no bleeding following administration of estrogen, then it may be due to outflow tract obstruction.

Positive Progesterone Challenge Test Result

  1. A positive Progesterone Challenge Test shows there is presence of uterus
  2. There is no obstruction in the reproductive tract, hence the blood flows out
  3. There is enough estrogen in the body

Progesterone Challenge Test Side Effects

  1. The Progesterone Challenge Test may provide inappropriately reassuring information that may delay the cause of ovarian insufficiency
  2. It should not be used as a substitute for evaluating the health of the ovaries as the health of ovaries must include assessing for serum estradiol and Follicle stimulating hormone (FSH)

The Progesterone Challenge Test is now rarely used because there are readily available laboratory tests that can measure serum estradiol and should only be done when there is confirmation that there is no pregnancy (that is, the woman is not pregnant).