Optimized Sonographic Weight Estimation of Fetuses over 3500 g Using Biometry-Guided Formula Selection.

Purpose The Hadlock et al. formula tends to underestimate fetal weight, in particular > 3500 g. At the high end of the range, the Merz et al. formula is more accurate, but becomes less so in smaller fetuses. This study was designed to improve fetal weight estimation in fetuses > 3500 g by identifying the fetal biometric parameter providing the most reliable guidance to optimal formula selection. Materials and Methods Regression analysis of 12 032 pregnancies showed that multiplication of abdominal circumference by femur length (AC × FL) gave the best choice of appropriate formula: Hadlock for AC × FL < 24 600, Merz for those ≥ 24 600. We then tested this rule, ('Zurich method'), prospectively in 4073 pregnancies, comparing it with the Hadlock, Merz and the Kehl formulas. Birth weights were merged into 7 categories (< 1500 to ≥ 4000 g, interval of 500 g). The percentage error (PE) and absolute percentage error (APE) were calculated. Results The PE using the Zurich method was lower in both > 3500 g groups than with the Hadlock formula alone (3500 - 3999 g: 0.9 % vs. - 5.3 %, > 4000 g: - 3.2 % vs. - 8.6 %), similar to that with the Merz formula alone, and lower than with the Kehl formulas (3500 - 3999 g: - 9.0 % vs. - 3.2 %, > 4000g: - 5.1 % vs. 0.9 %). The Zurich method and Hadlock formula also shared the lowest PE in the < 1500 g group: 0.2 % vs. 6.8 % (Kehl) vs. 9.6 % (Merz). In terms of APE the Zurich method performed almost as well as the Merz formula in the > 4000 g group, while sharing the lowest value with the Hadlock formula in the < 1500 g group (8.2 % vs. 10.5 % [Kehl], 23.6 % [Merz]). Conclusion The Zurich method uses a pivotal value of the biometry parameter AC × FL to switch between formulas and corrects for the errors of the Hadlock formula in fetuses ≥ 3500 g and those of the Merz formula in fetuses < 3500 g.

Congenital Lung Lesion: Prenatal Course, Therapy and Predictors of Perinatal Outcome.

Purpose To describe the prenatal course and perinatal outcome, and to define prognostic markers for fetuses with congenital pulmonary airway malformation (CPAM) or bronchopulmonary sequestration (BPS). Materials and Methods A retrospective study was performed at the University Hospital Zurich including pregnancies with either fetal CPAM (n = 26) or BPS (n = 11) between 2000 and 2013. Results Three patients decided for termination of pregnancy. Two intrauterine deaths (CPAM) occurred at 25 weeks. Minimally invasive interventions were performed in 9/37 (24 %) fetuses, post-interventional survival was 8/9 (89 %). Mean gestational age at delivery was 38.1 +/-2.8 and 39.1 +/-2.5 weeks in fetuses with CPAM or BPS, respectively. In fetuses with CPAM the perinatal mortality rate was 4/24 (17 %); the rate of invasive interventions or surgery during the early neonatal period (neonatal morbidity) was 9/22 (41 %). Prenatal diagnosis of hydrothorax and/or increasing cystic volume ratio (CVR) until delivery preceded perinatal death in 3/5 (60 %). Absent mediastinal shift showed a neonatal morbidity rate of 1/8 (13 %) without any perinatal mortality. In fetuses with BPS the perinatal morbidity and mortality were both 1/10 (10 %). Hydrops predicted morbidity and mortality in 100 % of cases. Absent hydrops was followed by uncomplicated perinatal outcome. Conclusion Fetuses with CPAM or BPS have a good outcome under optimal perinatal care including the possibility to perform minimally invasive prenatal interventions. CPAM without mediastinal shift and BPS without hydrops have an excellent prognosis. Hydrothorax, increasing CVR or hydrops indicates a high risk for perinatal morbidity and mortality.