The combined rst-trimester screening (CFTS) for fetal aneuploidy involves a combination of maternal age, fetal nuchal translucency (NT), maternal serum pregnancy-associated plasma protein-A(PAPP-A) and free β-human chorionic gonadotropin (β-hCG) from 11+0 to 13+6 weeks of gestation [1]. International prescriptive standards for early fetal linear size and ultrasound dating of pregnancy in the rst trimester are available and used throughout the world. Ethnicity has an effect on the biochemical parameters of rst trimester screening. As there is a lack of reference chart for the women of Indian ethnicity, we aimed to nd out the level of PAPP-Aand free β-hCG for fetal crown rump length (CRL) of 40-84 mm in the rst trimester of pregnancy and construct the centile charts for both the parameters. Asignicant but weak correlation between the individual models of PAPP-A and β-hCG and CRL (P<0.001). In conclusion, the normal range of PAPP-A and free β-hCG depending on the gestation (CRL) was derived in this cohort study. This would act as a reference for our population and would be helpful in calculating the risk of an adverse maternal and fetal outcome.