In a selected group of pregnant women we studied the influence of specific haematoclinical maternal factors (age, pre-pregnancy weight, pregnancy weight gain, blood pressure, haematocrit (HTC), haemoglobinaemia (Hb), platelets (PTL), uricaemia) on neonatal weight. The results show an association among pre-pregnancy low maternal weight, hypertension and low neonatal weight. The uricaemia behaviour and the role of PTL, Hb, HCT are uncertain.