Endocrine profiles and cycle characteristics of infertile 17α-hydroxylase/17,20-lyase Deficiency Patients undergoing assisted Reproduction Treatment: a retrospective cohort study

17α-hydroxylase/17,20-lyase deficiency (17-OHD) is a rare form of congenital adrenal hyperplasia caused by CYP17A1 gene variants. Female patients with 17-OHD demonstrate a broad clinical spectrum, including oligomenorrhea or amenorrhea and infertility, often as the sole manifestation. However, no spontaneous pregnancies in affected women have been reported.This retrospective cohort study aimed to explore the endocrine characteristics and assisted reproductive technique (ART) performance in women with 17-OHD.Five women were referred for primary infertility in a university-affiliated hospital over an eight-year period. The endocrine profiles and cycle characteristics during a total of nine cycles of ovarian stimulation and eight cycles of frozen-thawed embryo transfer (FET) were described in details.Three cases had homozygous variants and two cases had compound heterozygous variants, including one novel missense variant (p.Leu433Ser) in the CYP17A1 gene. Despite dual-suppression of progesterone (P) production by glucocorticoid and gonadotropin releasing hormone agonist, gradually increased P level, relatively low estradiol concentrations and thin endometrium were observed, negating fresh embryo transfer. During FET cycles, appropriate treatment resulted in low serum P levels and adequate endometrial thickness, leading to four live births.Our findings demonstrate that continuous elevation of serum P during follicular growth impairs endometrial receptivity, the likely cause of female infertility in 17-OHD. Therefore, female infertility caused by 17-OHD is suggested as an indication for freeze-all strategy, with promising reproductive prognoses following segmented ovarian stimulation and FET treatment.