This study was conducted to assess the corelation of prolactin with gestational age and birth weigh in a new born. Material and methods:Overall, 100 subjects had been recruited in this research. The participants were healthy, nulliparous women with singleton pregnancies. 50 case and 50 control samples were selected from the participants. Plasma samples obtained at 20 weeks of gestation were used. Following birth, pregnancy outcome data and infant measurements were recorded. Results: There were no differences between groups for any maternal characteristics. SGA cases were delivered earlier than controls. No significant differences were detected in maternal plasma prolactin concentrations between the uncomplicated pregnancy and SGA groups. No differences were seen between the uncomplicated pregnancy and SGA groups in prolactin concentrations when the foetus was female. When the foetus was male, maternal prolactin concentrations were significantly lower in SGA pregnancies compared to uncomplicated pregnancies. Significant correlation of prolactin levels with gestation age was seen. Conclusion: Prolactin at is likely to be useful biomarker for SGA, however this does not rule out its potential to be useful at a different time point of pregnancy