Clinical accuracy of estimated fetal weight in term pregnancies in a teaching hospital

Abstract

Objective To evaluate whether clinical characteristics alter the accuracy of clinical estimation of fetal weight (EFW) in term pregnancies in a teaching hospital. Methods Secondary analysis of a retrospective cohort study of patients presenting for labor at term. Clinical EFW was performed using Leopold maneuvers. A Spearman’s rank correlation coefficient (r) was used to evaluate the linear relationship between clinical EFW and actual birth weight (BW). Body mass index (BMI), gestational age, fetal station and admission diagnosis were evaluated with respect to their impact on clinical EFW. The primary outcome was an absolute error between clinical EFW and actual BW >500 grams. Results Of 3,797 patients, 941 (24.8%) had an absolute error in clinical EFW exceeding 500 grams. The overall correlation between clinical EFW and actual BW was weak (r=0.4). There was a significant trend of improved accuracy of clinical EFW with increasing gestational age; however, BMI, fetal station, and admission diagnosis did not have significant effects. 181 of 221 cases (81.9%) of fetal macrosomia (>4000 grams) were undetected by clinical EFW. Conclusion The correlation between clinical EFW and actual birth weight is overall weak, particularly in patients with macrosomic fetuses; however, BMI, admission diagnosis, and fetal station do not have a significant impact.

Predicting Cesarean Delivery After Induction of Labor Among Nulliparous Women at Term

“…The presence of meconium, male fetal sex, and fetal occiput posterior position have been previously associated with cesarean delivery (34–36). Although birthweight is a known predictor of cesarean delivery after IOL (13), this was not included in our model as it is a variable that is only known accurately post-delivery and estimated fetal weight antenatally both sonographically and clinically is weak (37, 38). …”

The utility of ultrasound surveillance of fluid and growth in obese women

“…17 In contrast, Goetzinger et al found no impact of BMI on the clinical estimation of fetal weight, although this study did include preterm patients. 18 Goetzinger et al also examined the ultrasound detection of fluid and growth abnormalities in those referred for size greater or less than dates in a population of mixed low- and high-risk women. 19 The detection of any abnormality was low (11–15%), but among patients referred for size greater than dates, the number needed to screen was increased in those with a BMI≥40 compared to those with a BMI <40.…”

Effect of Maternal Body Mass Index and Amniotic Fluid Index on the Accuracy of Sonographic Estimation of Fetal Weight in Late Gestation

“…Several prior studies have used these indicators to assess EFW accuracy and have used thresholds between 10 and 20% as a marker of inaccuracy. 2,9,12,13 These variables were calculated and/or defined as follows:…”