Objectives To develop and to evaluate a specific sonographic weight formula for fetuses with abdominal wall defects. Methods

Objectives To develop and test a specific formula for estimating weight in the macrosomic fetus. (3.69 (range, 0.05-13.57)%) when studied in the evaluation group. With the new formula, 77.9% of estimates fell within ± 5% of the actual weight at birth, 97.1% within ± 10%, and 100% within ± 15% and ± 20%. Methods ConclusionsThe new formula allows better weight estimation in the macrosomic fetus.

With proper application, our new formula can improve the accuracy of fetal weight estimation.

Objective: To develop new gender-specific regression formulae to estimate fetal weight focusing on a particular weight range from 2,501 to 3,999 g. Methods: 3,254 singleton pregnancies were included to generate new regression formulae for female and male fetuses, and to evaluate their accuracy. Results: In comparison with commonly used formulae, the new gender-specific and weight-range-specific method of fetal weight estimation provided greater accuracy. The mean absolute error was less than 7%. Conclusions: When properly used, the new formulae can improve the accuracy of weight estimations in fetuses between 2,501 and 3,999 g.

Oral poster abstracts +1.4847 (AC 2 ) −26.0729 (AC) −0.2637 (AVol 2 ) +52.5110 (AVol) +269. P < 0.0001; ''P = 0.0686; 'P > 0.05; ''P > 0.05; .P = 0.0455; ..P = 1.0000; P = 0.0143; P = 0.3173. Model parameter R-squared Conclusions:All 3 models systematically underestimated BW. To date, the AVol model has the greatest proportion of subjects that have been correctly classified for BW. OP08.07New specific ultrasound-based weight formula for fetuses with abdominal wall defects J. Siemer, A. Hilbert, N. C. Hart, B. Meurer, T. W. Goecke, R. L. Schild University Hospital Erlangen, Department of Obstetrics and Gynaecology, GermanyObjectives: Almost all commonly used formulae to estimate fetal weight by ultrasound include abdominal measurements. For fetuses with abdominal wall defects (AWD), they are not practicable. The aim of this study was to develop and evaluate a new formula for estimating weight in fetuses with AWD. Methods: Complete sonographic biometries were carried out within one week of delivery in 480 preterm singleton fetuses. Newborns with major structural or chromosomal anomalies, as well as intrauterine deaths, were excluded. Stepwise regression analysis with fetal biometric parameters (abdominal measurements were not considered) was used to identify the best-fit formula for predicting fetal weight at birth. Eventually, this new formula was evaluated in a group of 60 liveborn fetuses with AWD. Results:The new best-fit formula included biometric parameters of head and femur. Evaluated in the group of fetuses with AWD, the accuracy of the new formula for fetal weight estimation was similar to the accuracy of commonly used formulae in healthy newborns. Conclusions:The new formula allows reliable weight estimation in fetuses with AWD. OP08.08Cumulative sum (CUSUM) charts and tests: a simple method to assess the quality of fetal biometry. Objectives: Controlling for the distribution of biometrical measurements in comparison to reference measurements is a preliminary step for quality assessment. Z-scores have proven useful in such quality assessment processes. Cumulative sum (CUSUM) charts offer a simple way to detect changes in the mean of a quantity of interest. They focus on the cumulative sum of the deviations between the measurements and a target value. We aimed to assess the feasibility of CUSUM-based prospective monitoring of Z-scores as an ongoing quality assessment tool. Methods: Theoretically, Z-scores should follow a normal distribution with 0 and 1 for mean and standard deviation (SD) respectively. A single sonographer prospectively measured biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length (FL) at 20-24 weeks' gestation. All measurements were transformed into Z-scores. CUSUM charts and tests were used to pick up any deviation greater than half an SD in the distribution of Z-scores. Results: 1266 examinations were included. Mean and SD were all statistically different from 0 and 1, respectively. CUSUM charts and test allowed us to prospectively monitor ...