Should an Early Anatomy Ultrasound Scan Be Offered Routinely to Obese Pregnant Women?

Objective: The primary objective of this study was to determine whether an early anatomic scan (EAS), either on its own or in combination with the routine transabdominal scan (R-TAS), would improve overall completion rates of the fetal anatomic survey in the obese pregnant woman. The study's secondary objectives were to compare patients' and sonographers' satisfaction with EAS versus R-TAS.

Methods: A prospective observational study was carried out over a 2.5-year period including consecutive pregnant women with a pre-pregnancy BMI ≥30 kg/m who consented at a dating ultrasound appointment to undergo EAS at 15 ± 1 GA in addition to the second trimester R-TAS. Anatomic structures were categorized as normal, not well seen, or abnormal by using the institutional 26-item anatomic standardized reporting template. Examination completion and study duration were recorded. Neonatal follow-up was performed to evaluate for any missed diagnoses. Patients' and sonographers' satisfaction questionnaires were completed.

Results: A total of 120 pregnant women completed the study. Visualization of all anatomic components was complete in 14% at EAS and in 61% at R-TAS (combined completion rate, 90%). Mean scan time was 30.4 minutes at EAS and 51 minutes at R-TAS. No missed diagnoses of structural anomalies were identified at neonatal follow-up. EAS and R-TAS differed in terms of sonographers' reports of difficult or suboptimal scans (9% vs. 58%), well-seen anatomy (85% vs. 78%), and good visibility (44% vs. 12%). Most sonographers expressed a preference for performing EAS in future pregnancies, rather than the R-TAS (96% vs. 6%). Although patients reported greater satisfaction with EAS (93% vs. 74%), for reasons that could not be determined, they expressed a preference for R-TAS in a subsequent pregnancy (23% vs. 63%).

Conclusion: Performing EAS along with R-TAS improves completion rates for anatomic evaluation in the obese gravida and is associated with greater patient and sonographer satisfaction.