Modification ultrasonic methods estimating expected fetal weight

Selection of the optimal tactics of pregnancy and childbirth greatly depends on the expected weight of the fetus. Frequency of perinatal mortality and morbidity increased in grоup with growth retardation and fetal macrosomia. The aim of the study was a modification of ultrasonic methods for determining the expected fetal weight. Materials and methods. On the basis of maternity hospitals Trans-Baikal Region in the years 2013-2015 was held retrospective and prospective analysis of 210 labor histories, which were divided into 3 equal groups: 1 group - pregnant women with a body mass index (BMI) for Quetelet less than 24, group 2 - with a BMI from 24 to 30, group 3 - with a BMI more than 30. In order to determine the expected fetal weight by ultrasonic methods used formula of Hadlock, Shephard and Demidov. The error in determining fetal weight standard methods more than 250 g, which identified the need to establish new precise formula. The increase in the error in determining fetal weight at border gestation due to the lack of assessment of fetal tissue density. On the basis of mathematical and 3d-modeling of the body’s volume, depending on its mass determined pattern change of the average density of fetal tissue, depending on the gestational age, which is expressed by the formula: ρ = 0,833 + 0,004475GA, where ρ - the average density of tissue, GA - gestational age. Through a comprehensive analysis of ultrasound data’s fetometry and medium-density tissue defined fetal weight formula: M = (0,2777 + 0,001492 × GA) × OFD × AC × (Fe + Ti + Hu + Ra), where GA - gestational age (weeks), AC - abdominal circumference (cm), OFD - occipitofrontal diameter (cm), Fe - femur’s length (cm), Ti - tibia’s length (cm), Hu - humerus’s length (cm), Ra - radius’s length (cm), 0.2777 and 0.001492 - digital prognostic factors. In calculating the weight of the fetus according to the proposed formula ultrasonic average error does not exceed 150 g. Thus, the method has a smaller error compared to the standard, and can be used to reliably determine fetal weight in II and III trimester of pregnancy.

fetal weight, fetometry ultrasound, fetal macrosomia, fetal growth retardation