Comparative Estimation of Fetus Weight through Sonography and Clinical Techniques

Background: Regarding the significance of neonate weight estimate and certain complications due to inaccuracy in estimation and controversy over use of sonography or clinical techniques, this study was carried out on clients referring to Booali hospital in Tehran during the years ۲۰۰۳-۲۰۰۴. Materials and Methods: The Study was a cross-sectional research performed on ۳۰۰ qualified pregnant women (Over ۳۸ weeks of pregnancy). Estimation of fetal weight through clinical method was done using fundal height and standard measurement, while estimation of fetal weight through sonography was carried out by the physician using head and abdominal circumference, femur length and the corresponding formula. The cases were then followed up and their weights at birth were measured precisely. Acceptable estimates for values were ۱۰% ± real weight and ۲۰۰ gr± real weight at birth for each method. The data were analyzed through and Fisher’s exact test. Results: The research was carried out on ۳۰۰ qualified pregnant women in the age range of ۲۶ ± ۵.۴ and pregnancy age of ۳۹.۳±۱.۱ weeks and body mass index (BMI) of ۲۴ kg/m۲. Real body weight of neonates at birth was ۳۲۲۹ gr ± ۴۱۶.۷ with ۳.۷% over ۴۰۰۰ gr, ۲% under ۲۵۰۰ gr and the rest between ۲۵۰۰ gr to ۴۰۰۰ gr. In clinical method ۷۴.۶% and in sonography ۸۹.۳% of estimates were acceptable based on the scale of ۱۰% ± real weight (P=۰.۰۰۰۵). The above mentioned methods with the scale of ۲۰۰ real weight were acceptable as ۵۱.۶% and ۷۸.۳% respectively (P=۰.۰۰۰۵). Weight estimate by sonography in neonates under ۴۰۰۰ gr was preferable to clinical method while estimate by clinical method was more accurate in neonates over ۴۰۰۰ gr. (P=۰.۰۰۰۵) Conclusion: Concerning the extent of accuracy, some adverse effects, cost and time consumed to estimated weight in sonography it would be advisable to use clinical method under normal cricumstances and sonography in some certain situations.

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KEY WORDS: Birth weight , Clinical method of weight estimation , Sonography , Low birth weight , High birth weight (macrosomy)