Objective: To investigate the relationship between Day 8 serum luteinizing hormone (LH) and testosterone (T) concentrations, and body mass index (BMI) with pregnancy outcome in women with recurrent miscarriage. Design: Prospective observational study. Setting: National recurrent miscarriage clinic. Patient(s): Three hundred forty-four women (median age 32 years; range 18–44) with a history of recurrent first trimester miscarriage (median 4; 3–14; <12 weeks gestation) who conceived spontaneously and who received no pharmacological treatment during pregnancy were studied. All women were antiphospholipid antibody negative and had a normal peripheral karyotype as did their partners. Intervention(s): Outcome of untreated pregnancies. Main Outcome Measure(s): Day 8 serum LH and T concentrations and BMI were correlated with pregnancy outcome. Result(s): One hundred and ninety-two (55.8%) women had a live birth and 152 (44.2%) women miscarried. Polycystic ovarian morphology was diagnosed in 174 women (50.6%). There was no significant relationship between follicular phase LH concentrations and pregnancy outcome. Pregnancy outcome was similar in women with normal and high serum T concentrations. BMI value was not significantly different between women who had a live birth and those who miscarried. Conclusion(s): The analysis of this large cohort of women with recurrent miscarriage demonstrates that prepregnancy Day 8 serum LH and T concentrations, and BMI do not have a statistically significant relationship with pregnancy outcome.