A 32-year-old woman with classical congenital adrenal hyperplasia (CAH) secondary to 21-hydroxylase deficiency presented with infertility. She was treated with different steroid replacement regimens together with fludrocortisone. The aim of this case report is to discuss fertility barriers in women with classical CAH, and emphasise the risks and benefits of available steroid treatment options. Clinical considerations covered include preconception health and fertility planning, optimising fertility through suppression of excess hormone production, reducing fetal androgen exposure in utero and limiting maternal and fetal side effects of therapy and limiting chances of CAH in the baby. In this case suppression of androgen and progesterone levels was challenging but eventually was achieved and resulted in a spontaneous pregnancy. However, she miscarried in the first trimester, and fetal biopsy revealed a complete hydatiform mole. She is advised not to conceive while she is under investigation to determine the extent of the disease.