Objective: To determine the completion rate of ultrasound surveys for aneuploidy markers by maternal body mass index (BMI).
Methods: A retrospective review of ultrasounds on midtrimester singleton pregnancies was performed. Subjects were grouped as normal, overweight (BMI 25-29.9 kg/m(2)), and obese: class I (30-34.9 kg/m(2)), class II (35-39.9 kg/m(2)), and class III (>or= 40 kg/m(2)). Examinations with visualization of at least seven of eight markers were considered complete.
Results: Of 14 353 ultrasounds reviewed, 5690 patients were eligible: 43% normal, 29% overweight, 27% obese. Completion rates differed significantly between groups (64% normal, 64% overweight, 61% class I, 55% class II, 47% class III, p < 0.001). The screen positive rates (>or=1 marker) differed significantly overall (16% normal, 13% overweight, 15% class I, 12% class II, 10% class III, p < 0.02), but not for complete examinations (p = 0.42).
Conclusions: Since completion rates for ultrasound aneuploidy screening are inversely related to maternal obesity, obese women are underscreened.
(c) 2010 John Wiley & Sons, Ltd.