Accuracy and Completion Rate of the Fetal Anatomic Survey in the Super Obese Parturient.

Objective: To determine the completion rate of ultrasound in with a body mass index (BMI) ≥ 50 to women with BMI 18.5 to 29.9.

Study Design: This study was a retrospective cohort study. Women with a singleton pregnancy, age 18 to 45 with a BMI ≥50 that delivered between 2013-2016 were compared to women with a BMI 18.5 to 29.9 during that same time period to assess the accuracy and, as a second aim, the completion rate of the fetal anatomic survey. Data were analyzed using two-sample t test, chi-square test, or logistic regression as appropriate.

Results: Eighty-one cases with a BMI ≥50 were compared with 81 patients with a BMI 18.5 to 29.9. Maternal demographics and timing (gestational age) at the time of the ultrasound were similar between groups. In women with a BMI 18.5 to 29.9, completion of anatomy was 58% of the time with the first ultrasound, 81% with second ultrasound, and 84% with the third ultrasound. In women with BMI ≥50, completion of anatomy was 10% of the time with the first ultrasound, 33% with the second ultrasound, and 42% with the third ultrasound. Each time frame was statistically significant. Agreement level on the accuracy to detect fetal anomalies between groups were not statistically significant between the groups.

Conclusion: In women with a BMI ≥50 compared to women with BMI of 18.8 to 29.9, more ultrasounds are needed to complete the anatomic survey although overall accuracy in fetal anomaly detection is similar.