Ultrasound prediction of fetal birth weight in preterm delivery

Abstract

Introduction. The prediction of fetal birth weight is crucial for the establishment of a correct birth plan. It gives to the obstetrician a lot of useful information concerning the possible evolution of labor, the appearance of complications, the need for specific obstetrical intervention, and delivery by cesarean section and at an equipped center. The internationally accepted set of quality indicators for patient safety in obstetrics, eg. prenatal morbidity and mortality depend on an increase in abnormal birthweight range fetuses. The two main methods to predict fetal size are a clinical estimation and ultrasound measurement. The clinical evaluation of fetal weight is based on abdominal palpation of the fetus, determination of fundal height, body mass, or abdominal circonférence of the mothers subjective and not standardized. This is why the ultrasound examination is thought to be more helpful and accurate. The goal of the study was to assess the precision of the ultrasound in the prediction of fetal birth weight. Material and methods. This is a descriptive, non-experimental study of pregnant women hospitalized during 2017 in the Obstetrical department of Municipal Hospital No 1, Chisinau, Republic of Moldova. The pregnant patients were admitted to the hospital because of the pregnancy complication, or for delivery, or because of a high possibility of spontaneous onset of labor in the next few days. All the patients who were included in the study fulfilled the inclusion criteria. All the patients underwent ultrasound examination by the same experienced sonographer. The obtained fetal measurements were: Biparital diameter, Head circumference, Femur length, Humerus length, and Abdominal circumference by Gray-scale two-dimensional ultrasound. The results of these ultrasound data (head circumference, abdominal circumference, femur length, humerus length) were used to calculate the actual fetal weight. Birthweight was best estimated by different formulas: Chepard: Log10BW = 1.7492 + 0.0166 (BPD +) + 0.0046 (AC) - 0.00002646 (ACxBPD) Campbell: LnBW = 4.564 +: Log10BW = 1.326-0.0000326 (ACxFL) × 0.00107 (HC) + 0.00438 (AC) +0.0158 (FL), Hadlock Log10BW = 1.304 + 0.005251 (AC) + 0.01938 (FL) 0.00004 (Acx FL) 0.000016 (FL) 2 0.0000169 (FL), WarsofLnBW = 2.792 + 0.108 (FL) +0.000036 (ACxFL) + 0.00316x (BPD) +0.0045 (AC) +0.01623 ) 2-0.00027 (FLXAC), Combs BW = (0.00023718x (AC) 2x (FL) 2) +0.00003312 (HC), Ott Log10BW = 0.004355 (HC) +0.005394 (AC) -0.00008582 (HCxAC) +1.2594 (FL / AC) 0.326 + 0.00451 (SDI) +0.383,Deter EFW = 101.335-0.0034AcxFL + 0.0316BPD + 0.0457AC + 0.1623FLAll the pregant women delivered within 48 hoursfrom the ultrasound examination. The newborns were weighted 2 hours after the delivery using a graduated scale and the actual birth weights were recorded. The data collection was made by the extraction of the important information from medical files of the hospitalized patients, in accordance with the elaborated questionnaire for this research. Statistical processing was performed using the program “Microsoft Office Excel”. Results. A total number of 200 pregnant women were included in the study. From these 100 at term and 100 who delivered prematurely. The average age of mothers of children was 29.07 years, the age ranged from 21 to 42 years. The average weight of neonates' birth was 2057 gr. The difference between the estimated fetal weight by ultrasound and the birth weight of the fetus varied from 10 grams to 520 grams. The deviation from birth weight in thee formulas corresponded to Shield 187g, Hadlock 362, Deter 572g. The average difference was 355.71 grams. The difference <300 grams was 47.62%, > 300 grams was 52.38%. Conclusion. The ultrasound evaluation showed to have an average sensitivity in predicting the fetal weight at birth (47.6%). From the used formulas the Hadlock formula shows less deviation from neonatal weight in term deliveries and Shield formula in preterm. Accurate diagnosis of intrauterine fetal weight can be achieved by improvement of methods for assessing the foetal biometry.