Background: Previous studies in humans and mice have suggested the importance of leptin in fetal growth. Recurrent miscarriage may be a result of abnormal placental and/or fetal development and therefore abnormal leptin levels may be associated with this form of pregnancy loss.
Methods: Leptin and leptin-binding activity (LBA) were measured in blood obtained from women who had a history of recurrent miscarriage (n = 53) during weeks 5-6 and 7-8 of pregnancy, and the concentrations were correlated with subsequent pregnancy outcome.
Results: Concentrations of leptin ranged from 1.4-62.8 ng/ml, but there was a strong correlation (r = 0.825, P < 0.001) between leptin values at weeks 5-6 and 7-8 in the same woman. Women who subsequently miscarried had significantly lower plasma leptin concentrations on both weeks 5-6 (13.34 +/- 2.1 ng/ml) (P < 0.05) and 7-8 (13.71 +/- 2.4 ng/ml) (P < 0.01) of pregnancy, than women who subsequently had a term birth (22.04 +/- 2.43 ng/ml week 5-6, 24.76 +/- 3.66 ng/ml week 7-8). LBA values ranged from 1-8.5% but there was no significant difference in LBA in blood obtained from women who subsequently miscarried or had a live birth.
Conclusions: The significantly lower concentrations of leptin in women who subsequently miscarried suggest that leptin may play a role in preventing miscarriage. However, as there was a considerable overlap between the values of leptin in women who subsequently miscarried, and those that had a live birth, these measurements are of limited use in the prediction of pregnancy outcome in these women.