Does advanced ultrasound equipment improve the adequacy of ultrasound visualization of fetal cardiac structures in the obese gravid woman?

OBJECTIVE: This study was undertaken to determine the effect of advanced ultrasound equipment on the ability to visualize fetal cardiac structures in obese gravid women. STUDY
DESIGN: Singleton pregnancies undergoing initial ultrasound examination between 14 weeks and 23 weeks 6 days were included. Patients were classified by body mass index (BMI) (nonobese [BMI < 30 kg/m(2)] and obese [BMI > or =30 kg/m(2)]). The rate of suboptimal ultrasound visualization (SUV) of the fetal heart (cardiac axis, cardiac position, 4-chamber, and outflow tracts views) was compared between patients examined by standard (HDI 3000) or advanced ultrasound equipment (HDI 5000) (ATL, Philips Medical Systems, Bothell, Wash).
RESULTS: Over a 5-year period, 7029 singleton gestations met inclusion criteria; 2498 (35.5%) were clinically obese. There was no difference in gestational age, rate of low amniotic fluid volume, anterior placenta, or vertex fetal presentation between the groups. When the advanced ultrasound equipment was used, SUV of the fetal heart was lower in the nonobese population (20.8% vs 16.4%; P <.001), but not in the obese gravid women (38.1% vs 35.5%; P=.27). However, obese patients who were examined by advanced ultrasound equipment after 18 weeks had less SUV of the outflow tracts (28.5% vs 23.1%, P=.04) but not of the 4-chamber view.
CONCLUSION: Despite advanced ultrasound equipment, maternal obesity significantly limits visualization of the fetal heart. However, the advanced ultrasound equipment may somewhat benefit obese gravid women examined after 18 weeks' gestation