The remarkable discovery of fetal DNA in maternal circulation has opened up enormous possibilities of fetal genetic investigations. Therefore, an attempt has been made to develop a simple and reliable method for obtaining fetal DNA from maternal blood and establish its accuracy and sensitivity, so that it can be useful for prenatal diagnosis in developing countries. Blood samples were collected from pregnant mothers (n=255) recruited after informed consent and recording of clinical parameters. DNA was extracted from plasma, analyzed by PCR, detected sensitivity, specificity and accuracy of method using diagnostic tool. Total DNA increased from 157.09 to 608.15 GE during first to third trimester. PCR using Y chromosome specific primers showed 87.88, 94.44 and 94.70 % correct diagnosis during 1st, 2nd and 3rd trimesters respectively. Percentage of sensitivity, specificity, positive predictive value and accuracy of the method showed a gradual increase (83-100%) with advancement in gestation age. The overall sensitivity, specificity and positive predictive value were 89, 98 and 97% respectively with 94% method accuracy.
