الفهرس 
Fetal WeightOnly 14 pages are availabe for public view
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Abstract
Accurate estimation of fetal weight is one of the most important factors in successful planning and management of labour and delivery and it is still a topic of great interest in obstetrics.
Since its introduction into obstetrics in the late 1950s, ultrasound has played an increasingly important role in the characterization of normal fetal growth and the detection of fetal growth abnormalities. Fetal growth assessment is very important to clinicians as decrease or excess in fetal growth is associated with increased mortality and morbidity during the perinatal period.
Accurate EFW at delivery is crucial to evaluate the risk of morbidity and mortality in the foetus and neonate.
Accurate estimation of fetal weight has been shown to reduce perinatal morbidity and mortality associated with high risk pregnancy such as intrauterine growth retardation, macrosomia and prematurity.
None of the standard weight formulae consider fetal sex, despite compelling evidence of gender- specific differences between male and female infants.
The aim of the present study was to test the hypothesis that the sex-specific weight formula by Schild et al.(2004) compares favorably with Hadlock III formulae.
This prospective study was performed at Ain Shams University Maternity Hospital between January 2011 and July 2011. It included 320 pregnant women admitted to the delivery ward term, with singleton fetuses, Ultrasound examination with complete biometric parameters within 7 days of delivery and normal amniotic fluid index.
All measurements were performed by an expert operator experienced in fetal biometry using a trans-abdominal ultrasound with 5.0 MHz convex probe (Mindray DP-6900). Each fetus will be examined on a single occasion and only single readings will be used. Gestational age will be determined from the last menstrual period and confirmed by ultrasound, it will be given in exact weeks. Parameters like Bi-parietal diameter (BPD), Abdominal Circumference (AC), Femur length (FL) and Head Circumference (HC) will be measured, amniotic fluid had been assessed using amniotic fluid index method by dividing the abdomen into four quadrants then assuming measurements of amniotic fluid pockets in each quadrant.
The estimated fetal body weight was calculated twice as follow:
1- Hadlock’s formula, log10 EFW = 1.335 – 0.0034 AC
× FL + 0.0316 × BPD + 0.0457 × AC + 0.1623 × FL
2- Schild (female): EFW = –4,035.275 + 1.143 × BPD3
+ 1,159.878 × AC1/2 + 10.079 × FL3 – 81.277 × FL2
3- Schild (male): EFW = 43,576.579 + 1,913.853 × log10 BPD + 0.01323 × HC3 + 55.532 × AC2 – 3,602.664
× AC1/2 – 0.721 ×AC3 + 2.31 × FL3
Fetal body weight will be obtained immediately after delivery by a trained nursing staff. Babies will be weighed without wraps and with the umbilical cord and its clamp lift up to prevent errors in weighing. All fetuses were measured using the same calibrated scale.
This prospective study was analyzed and evaluated by comparing the results of EFBW using Schild formula and commonly used Hadlock formula and actual birth weight.
Actual birth weight was taken as the gold standard. Differences among estimated weights from the Schild formula, Hadlock formula and the actual birth weight was assessed by a paired t test.
Results:
The 49.7% of the studied infants were males and 50.3% of the studied infants were females from the total 320 studied fetuses and there is a higher mean fetal weight after birth among males (3.234kg) compared to females (3.052kg) and the difference is highly significant statistically.
There is lower mean percentage error (more accuracy) among the calculated weights by Schild equation (1.61) compared to Hadlock (2.1) and lower mean PE (more accuracy) among the calculated weights by Schild equation compared to Hadlock among males and females and also, there is lower mean percentage error among the calculated weights by Schild equation for males (-0.26) than females (3.4).
Among the studied fetuses there is a lower mean PE in Schild equation compared of Hadlock equation. There is also, a lower mean PE among males (-0.263) compared of females (3.4) according to Schild equation and the difference is highly significant statistically, also there is a lower mean PE among males (-1.082) compared of females (5.25) according to Hadlock equation and the difference is highly significant statistically.
A lower mean limits of agreement (more accuracy) is noticed among Schild equation (-34.9) compared to Hadlock (-45.1) by Bland Altman limits of agreement test also there is a lower mean limits of agreement (more accuracy) among Schild equation compared to Hadlock by Bland Altman limits of agreement test for male and female neonates.
There was a significant positive correlation between actual birth weight and each of EFW using Hadlock III formula and EFW using Schild’s formula, The highest correlation coefficient was with EFW using Schild’s formula [r=0.855, p<0.01], indicating the most significant association.