How does maternal obesity affect the routine fetal anatomic ultrasound?

To determine the completion rate for the routine anatomic survey in obese pregnant women with body mass index (BMI)≥30 as compared to normal weight controls (BMI: 20-25).

A retrospective analysis of the routine anatomic survey was performed in 100 consecutive women with a BMI≥30. Each subject was matched to two normal weight controls, controlling for gestational age. Exclusion criteria such as anatomic abnormalities or multiple gestations were known. The degree of visibility (satisfactory, moderate or unsatisfactory), indication for repeat examination and placental location were assessed.

Average BMI in the index cases was 35.7 (range: 30-64.8). Twenty-six (26%) of index cases were considered incomplete as compared to 5 (2.5%) of the 200 controls. The anatomic survey was completed in 74 (74%) of index cases compared with 195 (97.5%) of controls. Visibility was satisfactory in 28 (28%) of index cases, moderate in 46 (46%) and unsatisfactory in 26 (26%). In comparison, 177 (88.5%) were satisfactory, 17 (8.5%) moderate and 6 (3%) were poor in controls.

The completion rate for the routine anatomic survey in obese (BMI≥30) pregnant women was significantly lower as compared to normal weight pregnant women.