Congenital Adrenal Hyperplasia (CAH)

Definition - What does Congenital Adrenal Hyperplasia (CAH) mean?

Congenital adrenal hyperplasia (CAH) is a genetic disorder that causes low aldosterone (electrolyte balance hormone) and cortisol (stress hormone) production. The condition results in an overgrowth of cells in the adrenal glands in an attempt to compensate, leading to further hormonal imbalances, including overproduction of androgens (male sex hormones), thus affecting fertility.

The most severe cases include life-threatening electrolyte loss. Whether or not severe electrolyte imbalances are present, the exposure to elevated androgen levels during fetal development can lead to virilization of females in which genitalia appear male or ambiguous. These conditions are characteristic of classic CAH.

"Non-classic" cases of CAH are the mildest, but can still affect fertility. As in classic CAH, androgens are overproduced, so non-classic CAH symptoms are most noticeable in females. Women with CAH may show male characteristics such as excess body hair including facial hair. The clitoris may be enlarged. Ovulation and menstruation may happen irregularly or not at all, and progesterone levels can be constantly high, interfering with conception. Women with non-classic CAH may be able to conceive even without treatment, but many suffer from reduced fertility or infertility.

FertilitySmarts explains Congenital Adrenal Hyperplasia (CAH)

Symptoms of CAH in women may be confused with those of polycystic ovary syndrome (PCOS). Both conditions have symptoms that include elevated androgen levels leading to reduced ovulation and male sexual characteristics such as facial hair, but because treatment for the two conditions differs, it is important to correctly diagnose them.

Patients with CAH will need to take a hormone replacement for the missing cortisol and possibly another hormone to correct electrolyte imbalance. When the cortisol levels return to normal, the overgrowth of adrenal cells should cease, allowing levels of other hormones to return to normal. If regular ovulation in women does not then occur, clomiphene or a similar drug can be added to the treatment to induce ovulation if desired. Women may be prescribed anti-androgen drugs as well.

Surgical alteration of ambiguous genitalia in girls is possible. Many doctors recommend this surgery early in life, but others believe it may be best to wait until the child is older, to determine which gender the child identifies with so that the genitalia can match the child's preferred gender.

Men with CAH can also suffer from impaired fertility, primarily because they are prone to developing testicular adrenal rest tumors (TART). These benign tumors are formed from proliferating adrenal-type cells present in the testes. These cells then produce adrenal hormones that may interfere with sperm production, and the tissue masses themselves may block the sperm from leaving the testes. The risk of developing TART increases with age.

If eggs and sperm are both to come from people who carry a gene for CAH, in vitro fertilization (IVF) followed by pre-implantation genetic diagnosis (PGD) can ensure the embryo that is implanted does not have CAH.


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