Structured Abstract
Objective: Functional hypothalamic amenorrhoea (FHA) is a
common cause of amenorrhoea, but few non-specialist clinicians are able
to diagnose affected women. The aim of this study was to investigate the
clinical and biochemical features of FHA, compared to that of polycystic
ovarian syndrome (PCOS) and assess the diagnostic performance of the
different parameters for differentiating between the two conditions.
Design: A retrospective observational study
Setting: Specialist reproductive endocrine gynaecology clinic,
St Mary’s Hospital, London, UK
Population: Women diagnosed with FHA and PCOS following
specialist assessment.
Methods: Clinical and biochemical data were collected from
electronic hospital data base.
Results : Compared with PCOS, women with FHA had significantly
lower body mass index (BMI) (20.1±2.9 vs 31.1±7.8
kg/m2, P<0.0001) and a thinner endometrium
(3.75±2.23 vs 6.82±3.32 mm, P<0.0001). Women with FHA had
significantly lower luteinising hormone (LH) (3.46±7.31 vs 8.79±4.98
IU/L, P< 0.0001), as well as lower LH: follicle stimulating
hormone (FSH) ratio, estradiol, thyroid-stimulating, free thyroxine and
prolactin levels; there was no significant difference in FSH levels. Low
BMI had the greatest predictive performance for FHA (area under the
curve [AUC]; 0.93, P<0.001), followed by low estradiol
(AUC 0.89, P<0.001), low LH (AUC 0.88, P<0.001) and
LH:FSH ratio (AUC 0.86, P<0.001).
Conclusions :
Our data provides quantification for diagnostic accuracy of clinical
parameters to differentiate FHA from PCOS, namely low BMI, estradiol, LH
and LH:FSH ratio. These data could help clinicians more reliably
diagnose FHA in women with secondary amenorrhoea.
Key words: Amenorrhoea, Hypogonadism, Polycystic Ovarian
Syndrome, Luteinising Hormone
Tweetable abstract: Low BMI, estradiol, LH and LH:FSH ratio are
most effective at distinguishing FHA from PCOS.