Leptin is presumed to be related to body mass index (BMI) and body fat stores and is involved together with neuropeptid Y (NPY) in the regulation of appetite. As pregnancy is accompanied both by changes of BMI and appetite, performance of studies presented in this paper were fully justified. In 43 healthy pregnant women and in 18 pregnant women with mild or moderate EPH-gestosis, concentrations of leptin and NPY were estimated in maternal venous blood, umbilical cord blood and in amniotic fluid. The control group consisted of 26 healthy nonpregnant women. Healthy nonpregnant women showed a BMI of 23.08+/-0.65 kg/m2 which was significantly lower than in healthy pregnant women (26.9+/-0.4 kg/m2, p < 0.001) and in women with EPH-gestosis (29.7+/-0.9, p < 0.0001). Also in healthy pregnant women the BMI was significantly lower than in EPH-gestosis subjects (p < 0.001). In healthy nonpregnant women plasma leptin levels were significantly lower than in healthy pregnant and EPH-gestosis women (10.9+/-1.68 vs 14.99+/-1.28 vs 21.89+/-2.58 ng/ml, respectively). In umbilical cord blood plasma leptin levels were significantly lower than in maternal blood only in healthy pregnant women (7.37+/-0.69 vs 14.99+/-1.28 ng/ml) but not in EPH-gestosis subjects (18.06+/-3.38 vs 21.89+/-2.58 ng/ml). Leptin levels in amniotic fluid were significantly lower than in umbilical cord blood both in healthy pregnant women (2.25+/-0.20 vs 7.37+/-0.69 ng/ml) and EPH-gestosis women (6.58+/-2.62 vs 18.06+/-3.38 ng/ml). In EPH-gestosis women leptin levels were significantly higher than in healthy pregnant women in maternal blood (21.89+/-2.58 vs 14.99+/-1.28 ng/ml), umbilical cord blood (18.06+/-3.38 vs 7.37+/-0.69 ng/ml) and amniotic fluid (6.58+/-2.62 vs 2.25+/-0.2 ng/ml). In both examined pregnant groups plasma NPY levels were nonsignificantly lower in healthy pregnant and EPH-gestosis women (42.28+/-4.09 and 43.68+/-8.45 pg/ml, respectively) than in nonpregnant women 50.65+/-6.13 pg/ml). In normal pregnancy a significantly higher NPY level was found in umbilical cord blood as compared with respective values in EPH-gestosis women (116.28+/-17.0 vs 49.65+/-7.01 pg/ml). Finally in both examined groups of pregnant women the amniotic fluid NPY level was of similar magnitude (13.85+/-1.52 and 13.89+/-2.46 pg/ml in healthy pregnant and EPH-gestosis women respectively). No significant correlation was found between fetal birth weight and cord-serum leptin and NPY levels respectively.