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People with congenital adrenal hyperplasia (CAH) who are trying to conceive face fertility challenges from this hormonal condition that can’t be overlooked.
Measuring fertility and pregnancy rates in those with CAH is difficult due to several variables. In the past, women with classic CAH reported reduced fertility rates compared with fertility rates in the general population.
However, this picture has changed as CAH has become a better understood condition. More recent studies have found that women with classic CAH who desire to become pregnant can have fertility rates of around 90%, which is only a small amount lower than fertility rates that occur in the general population.
The higher fertility rates are due to a variety of factors. These include improved reproductive tools like in vitro fertilization (IVF), an emphasis on prenatal testing and a better understanding of the treatments needed to achieve hormonal balance while trying to conceive.
For those with nonclassic CAH that is being treated, the condition has minimal impact on fertility. And it mildly reduced fertility rates compared with fertility rates in the general population.
Female hormone balance disrupted
Classic CAH is characterized by the body producing an excess of male androgen hormones. This makes it much more difficult for women to get pregnant because the androgen hormone excess disrupts the balance of female hormones. This, in turn, suppresses ovulation and ovarian function. There has to be a careful balance between pituitary gland hormones — which stimulate the ovaries — and estrogen and progesterone for ovaries to ovulate, and for the uterus to respond appropriately, says Irina Bancos, M.D., M.S., an endocrinologist at Mayo Clinic in Rochester, Minnesota, who has led clinical trials and research into how to treat CAH more effectively.
When that balance is off due to CAH, a person may need a much higher dose of one of the main drugs used to treat CAH — for example, a glucocorticoid steroid such as hydrocortisone or prednisone. The drug helps lower male androgen hormones — and other adrenal hormones that are produced in excess — creating the conditions needed for pregnancy, Dr. Bancos says.
Nuances of increasing glucocorticoid therapy
Glucocorticoid therapy is required to replace the insufficiently produced adrenal hormone cortisol in people with CAH. Women with CAH often receive satisfactory treatment with relatively moderate-dose glucocorticoids, where dosing throughout the day also may be able to mimic the physiological ups and downs of natural cortisol needs.
When trying for pregnancy, moderate doses of glucocorticoids are far too low to foster the hormonal mix needed for fertility. Higher doses of glucocorticoid therapy are needed when trying to become pregnant. However, these higher doses have serious side effects with longer term use. Side effects include muscle loss, weight gain, increased blood sugar, osteoporosis, fractures, insomnia, depression and anxiety.
“When glucocorticoids are used in high doses, androgens do indeed decrease, and they even normalize. However, it’s quite unhealthy. When higher glucocorticoid doses are used for a long time, it leads to a lot of side effects. Resulting weight gain and elevated blood sugar — among other issues — can, in turn, also impact fertility, even if male hormones are brought into an acceptable range for fertility,” Dr. Bancos says.
Balancing the benefits of high glucocorticoid doses with the risks is a nuanced and individualized process. Sometimes, women on high doses of glucocorticoids become pregnant fairly quickly, and the duration of time on the high-dose treatment can be minimized, thus minimizing side effects.
But it’s often likely that conception takes time. In those who are taking longer to conceive, Dr. Bancos recommends consulting with a fertility expert in reproductive endocrinology to explore potential fertility treatments. This can help those with classic CAH keep the time spent on high-dose glucocorticoids to the shortest duration possible.
Added challenges
Men with classic CAH can have fertility challenges, too, especially if the condition is uncontrolled. Men with classic CAH can develop testicular adrenal rests. These are tumorlike lesions in the testes that can impact testicular tissue. This can lead to low testosterone and low sperm levels, which may lead to difficulty with fertility.
Another factor that may affect fertility relates to past genital reconstruction surgeries that a person with classic CAH may have had as a child or as an adult. However, no long-term study has been done to show that the effect of such procedures on the ability to conceive.
After conception
Once pregnant, women with classic CAH need to manage the condition during pregnancy. This includes appropriate management of the underlying adrenal hormone insufficiency, Dr. Bancos says.
If women with CAH are not already on high doses of glucocorticoids to help fertility, they may need to increase their glucocorticoid doses as the pregnancy progresses. If the prepregnancy glucocorticoid dose is already a high, supra-physiological dose, this change may not be needed.
People with adrenal insufficiency — including those with CAH — need appropriate education on adrenal crisis prevention, which can lead to death without prompt treatment. People with classic CAH should have a glucocorticoid injection kit and have education on how to use it.
Collaboration with the obstetrics team also is necessary to develop a plan for appropriate glucocorticoid therapy during delivery.
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