Congenital Adrenal Hyperplasia and Fertility: What Women Need to Know About Getting Pregnant With CAH

What Is Congenital Adrenal Hyperplasia and How Does It Affect Fertility?

Congenital adrenal hyperplasia refers to a group of autosomal recessive disorders caused by enzyme deficiencies in the cortisol biosynthesis pathway. The most common form, accounting for roughly 95% of cases, is 21-hydroxylase deficiency. This leads to reduced cortisol production, compensatory overproduction of adrenocorticotropic hormone (ACTH), and excess adrenal androgens — male-type hormones that can interfere with the female reproductive system.

In women with classic CAH, elevated androgens can suppress the hypothalamic-pituitary-ovarian axis, leading to irregular or absent menstrual cycles, anovulation, and reduced fertility. Research published in the Journal of Clinical Endocrinology & Metabolism has shown that women with the classic salt-wasting form of CAH tend to have lower fertility rates compared to both non-classic CAH patients and the general population. However, the non-classic (late-onset) form often presents milder fertility challenges that respond well to glucocorticoid therapy.

How Can Women With CAH Improve Their Chances of Pregnancy?

The cornerstone of fertility management in CAH is careful glucocorticoid replacement therapy. By adequately suppressing ACTH-driven androgen overproduction, clinicians can restore regular ovulatory cycles in many patients. Hydrocortisone is generally preferred during pregnancy due to its inability to cross the placenta in significant amounts, unlike dexamethasone. Endocrinologists typically aim to keep 17-hydroxyprogesterone and androstenedione levels within an acceptable range without over-suppressing cortisol, which carries its own risks including weight gain and bone density loss.

Preconception genetic counseling is also strongly recommended. Since CAH is autosomal recessive, both parents must carry a mutation for a child to be affected. Partner carrier testing can help families understand the likelihood of having a child with CAH. According to the Endocrine Society's clinical practice guidelines, women with CAH planning pregnancy should work with a multidisciplinary team including an endocrinologist, obstetrician experienced in high-risk pregnancies, and a genetic counselor. Assisted reproductive technologies such as ovulation induction may be considered when glucocorticoid adjustment alone does not restore fertility.

What Are the Risks During Pregnancy for Women With CAH?

Pregnancy in women with CAH requires close surveillance due to several elevated risks. Studies indicate higher rates of gestational diabetes, partly related to long-term glucocorticoid use, as well as increased likelihood of cesarean section — in some cases related to anatomical considerations following prior genital surgery. Adrenal crisis, though rare, is a serious concern, particularly during the physiological stress of labor and delivery. Stress-dose steroids are typically administered during labor to prevent this complication.

Despite these challenges, outcomes have improved considerably. Data from the European Society for Paediatric Endocrinology and published case series show that with appropriate endocrine management, the vast majority of pregnancies in women with CAH result in healthy live births. Neonatal screening programs, now standard in many countries, also ensure that any affected newborns are identified and treated promptly. The key message for women with CAH is that while fertility may require more planning and medical support, parenthood is a realistic and increasingly well-supported goal.