A scoring system for detection of macrosomia and prediction of shoulder dystocia: a disappointment.

OBJECTIVE: To develop a scoring system for the detection of a macrosomic fetus (birth weight (BW) >or= 4000 g) and predict shoulder dystocia among large for gestational age fetuses. STUDY DESIGN: We retrospectively identified all singletons with accurate gestational age (GA) that were large for GA (abdominal circumference (AC) or estimated fetal weight (EFW) >or= 90% for GA) at >or=37 weeks with delivery within three weeks. The scoring system was: 2 points for biparietal diameter, head circumference, AC, or femur length >or=90% for GA, or if the amniotic fluid index (AFI) was >or=24 cm; for biometric parameters <90% or with AFI <24 cm, 0 points. The predictive values for detection of shoulder dystocia were calculated. RESULTS: Of the 225 cohorts that met the inclusion criteria the rate of macrosomia was 39% and among vaginal deliveries (n = 120) shoulder dystocia occurred in 12% (15/120; 95% confidence interval (CI) 7-20%). The sensitivity of EFW >or=4500 g to identify a newborn with shoulder dystocia was 0% (95% CI 0-21%), positive predictive values 0% (95% CI 0-46%), and likelihood ratio of 0. For a macrosomia score >6, the corresponding values were 20% (4-48%), 25% (5-57%) and 2.3. CONCLUSION: Though the scoring system can identify macrosomia, it offers no advantage over EFW. The scoring system and EFW are poor predictors of shoulder dystocia.

Sonographic estimate of birth weight among high-risk patients: feasibility and factors influencing accuracy.

OBJECTIVE: This study was undertaken to determine the feasibility of detecting abnormal fetal growth among patients undergoing biophysical profile (BPP) and to identify the factors those influence the accuracy. STUDY DESIGN: Retrospectively singletons with reliable gestational age (GA) having a BPP were identified. Fetal growth restriction (FGR) and large-for-gestational age (LGA) were based on estimated or actual birth weight 10% or less or 90% or greater for GA, respectively. Likelihood ratio (LR), odds ratio (OR) and 95% CIs were calculated and multivariate predictive models used. RESULTS: Among the 1934 consecutive patients that met the inclusion criteria, the LR of detecting FGR was 10.9 and of LGA, 17.4. Multivariate analysis indicates that accurate classification of fetal growth is significantly better with hydramnios (OR 1.78, 95% CI 2.68), if the GA is less than 32 weeks (OR 3.71, 95% CI 1.50-9.16) or GA is between 32.1 and 36.9 weeks (OR 1.43, 95% CI 1.05-1.96). CONCLUSION: It is feasible to accurately identify abnormal growth among high-risk patients and to delineate factors that influence the correct classification of fetal growth.