PLOD1 and hypogonadotropic hypogonadism: After the administration of GnRH analogues, a functional state of hypogonadotropic hypogonadism with LH deficiency could be achieved, potentially affecting folliculogenesis, steroidogenesis and oocyte competence, impinging on clinical outcomes. The concept of serum LH dynamic changes following GnRH analogue employment as an indicator for LH threshold should be pursued, instead of a single serum LH evaluation.