Objective To evaluate the time required and failure rate for completion of nuchal translucency thickness (NT) measurements with increased maternal body mass index (BMI).
Methods BMI (normal weight group, 9.7 (interquartile range (IQR) 4.4, 19.0) min; overweight group, 8.8 (4.0, 19.8) min; obese Class I, 9.6 (4.8, 20.4) min; Class II, 14.1 (5.0, 28.2) min; Class III, 12.3 (4.6,22.7) min; P < 0.01), as did the total study time (normal group, 16.4 (10.1, 26.6) min; overweight group, 15.7 (9.8, 25.0) min, Class I, 17.3 (10.3, 29.2) min; Class II, 23.0 (12.2, 36.1) min; Class III, 18.7 (11.0, 30.8) min; P = 0.002). For all attempts also, the median time for NT measurement varied significantly according to BMI (normal weight group, 9.7 (IQR 4.4, 19.0) min; overweight group, 8.8 (4.0, 19.9) min; obese Class I, 9.6 (4.8, 21.0) min; Class II, 14.1 (5.0, 28.7) min; Class III, 12.3 (4.6, 22.5) min; P < 0.01), as did the total study time (normal weight group, 16.4 (10.2, 26.7) min; overweight group, 15.7 (9.8, 25.1) min; Class I, 17.6 (10.4, 29.9) min; Class II, 23.2 (12.0, 37.5) min; Class III, 18.7 (11.9, 31.9) min; P < 0.001).
Conclusion
