The possibility of modifications methods of determine volume of amniotic fluid

Abstract

Selection of the optimal tactics of pregnancy and childbirth significantly depends on the expected volume of amniotic fluid. The amount of amniotic fluid reflects a condition of a fetus and changes at pathological conditions of both a fetus, and an uteroplacental complex. The aim of the study was a modification of methods for determining the expected volume of amniotic fluid. On the basis of maternity hospitals Trans-Baikal Region in the years 2013-2015 was held retrospective and prospective analysis of 300 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 volume of amniotic fluid were used the subjective method, the Chamberlain’s and Phelan’s methods. The error in determining volume of amniotic fluid by the existing methods exceeds 10 %, that defined need of creation of a quantitative method. On the basis of mathematical and 3d-modeling of the volume of amniotic fluid and fetal weight determined pattern change, which is expressed by the formula: VAF = IAF × М × π / GA2, where IAF - index of amniotic fluid (mm), M - fetal weight (g), GA - gestational age (weeks). Through a comprehensive analysis of anthropometric research of the pregnant women defined formula’s volume of amniotic fluid: V = 0,017 × HUF × (AC - 25 × BMI / GA)2 - М, where GA - gestational age (weeks), AC - abdominal circumference of the pregnant women (cm), BMI - body mass index for Quetelet in the first trimester of pregnancy (kg/m2), HUF - height of an uterine fundus (cm), M - the estimated fetal weight (g). In calculating volume of amniotic fluid according to the proposed ultrasonic formula error does not exceed 5,3 %, anthropometric formula error does not exceed 10,2 %. Thus, the method has a smaller error compared to the standard, and can be used to reliably determine volume of amniotic fluid in II and III trimester of pregnancy.