Reference Charts of Fetal Biometric Parameters at Different Gestational Age Groups in Indian Population

To develop, a reference charts of fetal abdominal circumference and femur length in normal pregnant women by using ultrasonography for Indian population. Further comparison of our findings with data derived from different population. This retrospective cross-sectional study included 300 normal singleton pregnancies and was carried out in the department of Anatomy, All India Institute of Medical Sciences, Jodhpur (Rajasthan), India from September 2017 to April 2019. Ultrasonography measurements included Abdominal circumference (AC) and Femur length (FL). Reference charts with mean AC and FL for corresponding Gestational age (GA) in weeks were developed. Also reference centiles (10th, 50th, 90th and 95th) were derived from this model and compared with similar studies done on different population. There was no statistically significant difference in age distribution of pregnant women (p=0.87). Both AC and FL were found to have statistically significant linear relationship with advancing gestational age (p=0.0005 & p=0.0003 respectively). There is significant difference observed between the values obtained in present study with studies concluded on Chinese and European population. Measurement of AC and FL are used to predict gestational age of fetus by using various regression formulae, also AC is known to be good predictor of nutritional status of fetus in utero. A separate chart is required for every different population because ethnicity, nutrition and environmental factor can have impact on normal values. Therefore, a reference chart for these parameters according to Indian population standards is essential to avoid misinterpretation of data. This would help to avoid misdiagnosis of intrauterine growth retardation or macrosomia during prenatal and perinatal period.