BACKGROUND: It has been recently suggested that gonadotrophin-releasing hormone agonist down-regulation in some normogonadotrophic women may result in profound suppression of LH concentrations, impairing adequate oestradiol synthesis and IVF and pregnancy outcome. The aims of this study, where receiver-operating characteristic (ROC) analysis was used, were: (i) to assess the usefulness of serum LH measurement on stimulation day 7 (S7) as a predictor of ovarian response, IVF outcome, implantation, and the outcome of pregnancy in patients treated with recombinant FSH under pituitary suppression; and (ii) to define the best threshold value, if any, to discriminate between women with 'low' or 'normal' LH concentrations. METHODS: A total of 144 infertile women undergoing IVF/intracytoplasmic sperm injection (ICSI) treatment were included. Seventy-two consecutive patients having a positive pregnancy test (including 58 ongoing pregnancies and 14 early pregnancy losses) were initially selected. As a control non-pregnant group, the next non-conception IVF/ICSI cycle after each conceptual cycle in our assisted reproduction programme was used. RESULTS: The median and range of LH values in non-conception cycles, conception cycles, ongoing pregnancies, and early pregnancy losses, clearly overlapped. ROC analysis showed that serum LH concentration on S7 was unable to discriminate between conception and non-conception cycles (AUC(ROC) = 0.52; 95% CI: 0.44 to 0.61) or ongoing pregnancy versus early pregnancy loss groups (AUC(ROC) = 0.59; 95% CI: 0.46 to 0.70). To assess further the potential impact of suppressed concentrations of circulating LH during ovarian stimulation on the outcome of IVF/ICSI treatment, the three threshold values of mid-follicular serum LH proposed in the literature (<1, less than or equal to0.7, <0.5 IU/I) to discriminate between women with 'low' or 'normal' LH were applied to our study population. No significant differences were found with respect to ovarian response, IVF/ICSI outcome, implantation, and the outcome of pregnancy between 'low' and 'normal' S7 LH women as defined by those threshold values. CONCLUSIONS: Our results do not support the need for additional exogenous LH supplementation in down-regulated women receiving a recombinant FSH-only preparation.
