Aetiology and Clinical Characteristics of Primary Amenorrhoea with Hypothalamic or Pituitary Disorders at a Quaternary Hospital.

Background/purpose of the study: To identify the causes and clinical characteristics of women with primary amenorrhoea and hypothalamic or pituitary gland disorders. Methods: This retrospective study was conducted at a quaternary hospital in southern Thailand. The medical records of women diagnosed with primary amenorrhea and hypothalamic or pituitary gland disorders (hypogonadotropic hypogonadism [HH]) were reviewed. HH was defined as an oestradiol level of < 20 pg/mL, decreased (< 5 mIU/mL) or normal serum follicle-stimulating hormone (FSH) levels, and no organic disease of the uterus or ovaries. Results: Fifty-five women with HH were included. The median (interquartile range [IQR]) age at presentation was 18 years (range, 17-20 years). Most patients presented with primary amenorrhoea (50/55), followed by primary infertility (3/55). All women had low levels of oestradiol (5 pg/mL [5.0-12.1]), FSH (0.8 mIU/mL [0.3-3.7]), and luteinising hormone (0.5 mIU/mL [0.1-2.3]). The most common cause was hypothalamic dysfunction (80%); including congenital hypogonadotropic hypogonadism (CHH) (43.6%), constitutional delay of growth and puberty (CDGP) (14.5%), and functional hypogonadotropic hypogonadism (FHH) (10.9%). Regarding hypothalamic dysfunction, patients with CHH were significantly older than those with CDGP (20 years [17.0-26.5] vs. 16.5 years [15.8-17.2]; P = 0.014) and had significantly lower FSH levels compared to those with FHH (0.6 mIU/mL [0.3-1.0] vs. 4.5 mIU/mL [2.8-5.7]; P = 0.026). Conclusion: Hypothalamic dysfunction, particularly CHH, is the most common cause of primary amenorrhoea and HH.