In this study the relation between maternal age, spacing number of pregnancies and birth weight and height was evaluated 1000 newborns in Fatemeh hospital in Hamedan. The growth parameters of newborns from mothers aged 18-35 years, were more than newborns from mothers under 18 or over 35 years. Also infants born from mothers, how had less than 24 months interval between pregnancies weight less and were shorter in height than newborns from mothers how had more than 24 mothers between pregnancies. In first born babies the growth parameters were lower than those born from mothers with multiple pregnancies. The results indicate that the number of low birth weight neonates will be decreased with pregnancy between 18 to 35 years and spacing more than 24 mothers.