Abstract 525

Background: In preeclampsia maternal plasma leptin is elevated, which has been attributed to increased placental production of the hormone under hypoxic conditions. Erythropoietin (EPO) is an indicator of hypoxia. We studied the effect of hypoxia on fetal leptin. Subjects: Cord blood samples were taken from 39 infants delivered by elective cesarean section. GA was 35.3-39.3 wks, BW was 1905-5430 g, relative BW -3.2 - +5.6 SD, Apgar score 7-10, and cord artery pH 7.15-7.40. 23 mothers had insulin dependent diabetes mellitus, and 9 preeclampsia. Results: Cord leptin concentration was 1.85-135.1 µg/L and EPO 6-9263 mU/mL. Correlations existed between leptin and EPO (R=0.61, P=0.0001), BW (R=0.53, P=0.006), and relative BW (R=0.67, P=0.0001); a negative correlation was found between leptin and cord artery pH (R=-0.45, P=0.004). In multiple regression analysis with relative BW, cord artery pH, and EPO as independent variables, and leptin as dependent variable, EPO (partial R=0.39, P=0.0019) and relative BW (partial R=0.52, P=0.0001) were significantly associated with leptin. Conclusions: Hypoxia increases fetal leptin. This may play a physiologic role in adaptation to chronic hypoxia.