Correlation Analysis Between Amniotic Fluid Index And Fetal Weight In Full-term Pregnancy

Background: With the increasing expectations of obstetric delivery safety, the scientific and accurate estimation of fetal weight is becoming more important. The accurate prediction of fetal weight before birth and the accurate predict physiological indexes will reduce the damage to the fetus during delivery, reduce obstetric labor complications, reduce the perinatal infant disability and mortality. Based on this, the prediction of fetal weight has become an important basic subject in the field of obstetrics. Up to now, the height of uterus, abdominal circumference, fetal biparietal diameter and femur length were normally used in estimating the fetal weight. It is unclear that whether the amniotic fluid index(AFI) affect the fetal weight during full-term pregnancy, and there is no relative formula using AFI to predict the fetal weight.Objective: To collect the maternal clinical data according to the routine examination of maternal, record the fetal actual weight.To investigate the correlation between AFI and fetal weight and identify the effect of AFI on the prediction of fetal weight in full-term pregnancy by correlation and mata-regression analysis. To establish a formula including AFI to predicting fetal weight and clear the role of AFI in fetal weight prediction.Methods: The clinical data from 123 cases of full-term pregnant, 155-174 cm height,37-42 gestational weeks, normal pregnancy without any complication in Shanxian Zhengda hospital of Shandong province from November 2014 to June 2015 was recorded. The uterine height and abdominal circumference of pregnant women was routinely detected. The AFI, fetal biparietal diameter and femur length was measured by type-B ultrasonic. The correlation between AFI and fetal weight or other indexes was analyzed and the new regression equation including AFI was established. The fetal weight was calculated by the new regression equation, and the deviation between actual fetal weight and predicted weight was compared with other prediction methods.Results: The average fetal weight in that of lower AFI( 5-7.9cm) was significantly lower than that of normal AFI( 8-23.9cm)(P <0. 05). There was a significant positive correction between AFI and fetal weight(P <0. 01). There was also positive correlation between AFI and uterine height or abdominal circumference(P<0.01 or P<0.05). There was no significant positive correction between AFI and fetal biparietal diameter or femur length(P >0. 05). After the AFI was added to the new regression formula, the predicted error of the fetal birth weight was significantly smaller than that by other formulas. Using the new formula with AFI + uterine height + abdominal circumference, the coincidence rate of fetal prediction weight is higher than that using the formula with single AFI.Conclusion:1. AFI was significantly associated with fetal weight.2. After the AFI was added to the new regression formula, the predicted error of the fetal birth weight was significantly smaller than that by other formulas.2. The coincidence rate of fetal prediction weight is higher by the new formula with AFI + uterine height + abdominal circumference than that by the formula with single AFI.