Cardiovascular disorders are the main cause of maternal mortality. electrocardiograms play important role in understanding these changes in pregnant women in first trimester. Aim and Objectives: To study the effect of normal pregnancy on the electrocardiogram. Materials & Method: This study was conducted on 40 young healthy subject having good physical condition. 40 healthy non pregnant women of the same age group were selected randomly from general population. We explained and demonstrate to all subjects about study and consent was taken from each subject. Subjects were allowed to take rest for ten minutes. Recording of resting pulse rate done by palpating the radial artery and blood pressure was recorded with a mercury sphygmomanometer. A 12 lead ECG was recorded by using ECG machine with special emphasis on changes in heart rate, PR interval, QT interval, all the parameters were analyzed. Results: The ECG changes observed in our study include, significant increase in heart rate and increase in QT interval, decrease in PR interval when compared to normal non pregnant women. Conclusion: This study proved that increment in heart rate is significant compared to control group. Decrease PR interval and increase QT interval is not significant. Now we can conclude that there is need to further evaluation cardiac changes during antenatal period.