It's not a very popular test, albeit costly. It should not be done in all cases.
What is it?
17 hydroxy progesterone (17OHP) is a steroid produced by the adrenal glands of both male and female, ovaries and testes. It is converted into other steroid hormones like corticosteroid (controls body metabolism), androgen (male sex hormone) and estrogen (female sex hormone).
When it is raised?
In some conditions, the enzymes necessary for conversion of 17OHP to corticosteroid is absent. As a result, corticosteroid may be deficient and the 17OHP is converted to androgen in excess amount. This condition is called CAH (Congenital Adrenal Hyperplasia). It is hereditary disease, so can be transmitted from one generation to another.
CAH is of 3 categories.
1. Classical CAH- The most severe variety. It manifests soon after birth. The baby is born with ambiguous genitalia (sex determination by looking at the genitalia is difficult) and salt wasting (salts are lost through urine), which is life threatening and needs Emergency Medical Attention to save the baby. These woman need Corticosteroid replacement throughout their lives. They may even need Genital surgery and Infertility-Treatment later on.
2. Partial CAH- Less severe form. It manifests at birth with Ambiguous Genitalia but No Salt Wasting. It needs corticosteroid replacement to suppress excess androgen.
3. Non-classical or Late Onset CAH- The mildest form. Genitalia are like normal females. It usually is diagnosed after puberty. It can cause PCOS like features and can coexist with PCOS. The symptoms are irregular periods, excess hair growth (like men), oily skin and excessive pimples. They can have early start of menstrual periods in their childhood. They need mild dose of corticosteroid to prevent these symptoms and to help in achieving pregnancy.
When to test for 17OHP?
All women with irregular periods or PCOS do NOT need this test. It is done ONLY if CAH is suspected.They are-.
A) If the period was irregular right from the beginning (when period started in childhood). That's why, we ask "Since when periods become irregular". If periods become irregular for few years, 17OHP test is NOT required.
B ) Family history of CAH in a woman with irregular periods.
C) In some ethnic groups like Ashkenazi Jews, where CAH is highly prevalent.
What's the next step?
In some cases, where 17OHP is mildly elevated, another test, ACTH stimulation Test needs to be done. Then low dise steroid (usually at bed time) is started after consultation with Endocrinologist.
What is the outcome?
In most cases if Non-Classical CAH, majority of the women will have regular periods, abnormal hair growth will cease and will conceive. Usually, there is no serious side effect with such low dose of steroids.