Accuracy of OBGYN Resident Physician Clinical Estimation of Fetal Weight in Term Pregnancies Before and After a Teaching Curriculum
Authors: Jois Madhuri , Adam Kailynn , Patel Ravi , Griffin Annie , Ryan Kelly , Lusby Christine , Lynn Mary , Pham Thythy , Frenn Recia 
Published: July 2024

Purpose: Accurate prediction of fetal birth weight can improve antepartum and intrapartum shared decision-making with patients. Therefore, this study primarily sought to determine if OBGYN residents are more accurate at clinically estimating fetal weight via Leopold maneuvers following a teaching curriculum including a hands-on simulation model. Secondary aims were to determine if accuracy changes depending on training level, maternal or fetal characteristics.

Methods: A paired t-test was used to evaluate the primary aim of the teaching curriculum’s effect on accuracy of correct fetal weight estimation. Nineteen residents served as their own controls to assess differences in accuracy by performing 10-12 estimates prior to and after the teaching curriculum. The curriculum consisted of a short verbal workshop with images of how to perform Leopold maneuvers, along with five models that were created to represent a gravid uterus with a fetus measured in the 5th, 25th, 50th, 75th, 95th percentiles. Residents were also tested on models with unknown weights to confirm accuracy prior to completing the teaching curriculum. The inclusion criteria during the fetal weight estimates pre- and post-curriculum was as follows: mother had to deliver during hospital admission; gestational age was between 37 weeks and 41 weeks; singleton pregnancy; mother had not undergone rupture of membranes; mother was English speaking. Accuracy was defined as estimated fetal weight within 10% of actual birth weight. Generalized Logistic Mixed Models were used to assess accuracy when adjusting for PGY level, maternal and fetal characteristics. Maternal characteristics including age, BMI, race, pregestational diabetes, gestational diabetes, polyhydramnios, and oligohydramnios were abstracted from maternal medical charts via retrospective chart review. Infant characteristics including fetal macrosomia, fetal growth restriction, and gestational age were also recorded. Analyses were conducted using SAS 9.4; all p-values were two-sided and p-values <0.05 were deemed statistically significant.

Results: Nineteen OBGYN residents performed a total of 443 Leopold maneuvers to estimate fetal weight. Overall, resident estimation accuracy within 10% of actual birth weight improved from 65.5% to 67.4% (p=0.49) after the teaching curriculum. Senior residents showed a greater improvement after the teaching curriculum than junior residents, however it was not statistically significant. This could be due to the low sample size. Increasing gestational age was associated with higher odds of accurate estimation of fetal weight (OR 1.34, p=0.0295). There were no other differences in accuracy based on other maternal or fetal factors.

Conclusion: The teaching of Leopold maneuvers is often not formalized in residency programs. This study did not show the expected improvement in accuracy of fetal weight estimation. Considerations that may impact clinical estimations include improving the simulation model, revising the teaching curriculum, and/or doing the teaching curriculum more frequently. Incorporating this hands-on simulation annually within the residency program educational curriculum to standardize the learning experience may be beneficial.