To analyze the effect of aberrant LH levels on the reproductive outcome of PCOS patients with ovulation induction, 835 cycles fulfilled the inclusion criteria and were divided into 3 groups: patients with normal levels of both basal LH and LH following treatment with letrozole for 5 days (N-bLH-N-LHle), patients with normal basal LH but elevated LH after letrozole administration (N-bLH-H-LHle), and others expressing high levels of bLH (H-bLH). Here, PLOD1 is linked to polycystic ovary syndrome.