Assessment of fetal gestational age by ultrasonic measurement of bi-parietal diameter in the southern part of Rajasthan

Abstract

<b>Introduction:</b> Assessment of gestational age (GA) in pregnancy can be carried out by measuring several fetal parameters in ultrasound scans and serial ultrasounds can monitor fetal growth. This study was carried out to assess GA in second and third trimesters with the help of ultrasonography measurements of one of the important fetal parameter that is, the bi-parietal diameter (BPD) in the local population (southern zone) of Rajasthan. <b>Aim:</b> The aim was to provide data for GA estimation by ultrasonic measurement of fetal BPD. <b>Materials</b> <b>and</b> <b>Methods:</b> A total of 200 normal pregnant females were studied with the known last menstrual period in the southern part of Rajasthan. GA determined by measurement of fetal BPD with real time ultrasonography machine. Statistics was applied to correlate GA and BPD. <b>Observation</b> <b>and</b> <b>Results:</b> In this study, fetal mean BPD showed a linear increase from 13 to 36 weeks. Statistically significant correlation was found between GA and BPD (<i>r</i> = 0.38). Mean BPD showed an increase of 2.38 cm in 13-20 weeks, 2.18 cm between 20 and 27 weeks and only 1.72 cm from 27 to 34 weeks. Average growth rate of BPD was found to be 0.31 cm/week from 13 to 28 week, which then later reduced to 0.23 cm/week from 28 to 36 weeks of gestation. <b>Conclusion:</b> Bi-parietal diameter is one of the useful criteria to measure GA and to predict expected date of delivery. Mean measurements of BPD in this study was found to be lower than that of western studies except Hadlock series, which compares well with this study. The mean BPD values of this study compares well with some Indian studies and other found higher results. Variation in predicted values is attributed to anthropometric differences between the two populations due to racial, genetic, nutritional, and socioeconomic factor. Therefore, large scale studies should be done and population-specific tables should be derived to correlate BPD and GA.