A few studies have measured LH concentrations during ovulation induction with FSH preparations (Coelingh Bennink et al., 1998; Balasch et al., 2003), but the impact of endogenous LH concentrations during or at the end of gonadotrophin stimulation on treatment outcome in PCOS patients has not been specifically addressed. The gene discussed is PLOD1; the disease is polycystic ovary syndrome.