United States' experience in nuchal translucency measurement: variation according to provider characteristics in over five million ultrasound examinations.

OBJECTIVE: The Nuchal Translucency Quality Review (NTQR) program has provided standardized education, credentialing and epidemiological monitoring of nuchal translucency (NT) measurements since 2005. Our aim was to review the effect on NT measurement of provider characteristics since the program's inception. METHODS: We evaluated the distribution of NT measurements performed between January 2005 and December 2019, for each of the three primary performance indicators of NT measurement (NT median multiples of the median (MoM), SD of log10 NT MoM and slope of NT with respect to crown-rump length (CRL)) for all providers within the NTQR program with more than 30 paired NT/CRL results. Provider characteristics explored as potential sources of variability included: number of NT ultrasound examinations performed annually (annual scan volume of the provider), duration of participation in the NTQR program, initial credentialing by an alternative pathway, provider type (physician vs sonographer) and number of NT-credentialed providers within the practice (size of practice). Each of these provider characteristics was evaluated for its effect on NT median MoM and geometric mean of the NT median MoM weighted for the number of ultrasound scans, and multiple regression was performed across all variables to control for potential confounders. RESULTS: Of 5 216 663 NT measurements from 9340 providers at 3319 sites, the majority (75%) of providers had an NT median MoM within the acceptable range of 0.9-1.1 and 85.5% had NT median MoM not statistically significantly outside this range. Provider characteristics associated with measurement within the expected range of performance included higher volume of NT scans performed annually, practice at a site with larger numbers of other NT-credentialed providers, longer duration of participation in the NTQR program and alternative initial credentialing pathway. CONCLUSIONS: Annual scan volume, duration of participation in the NTQR program, alternative initial credentialing pathway and number of other NT-credentialed providers within the practice are all associated with outcome metrics indicating quality of performance. It is critical that providers participate in ongoing quality assessment of NT measurement to maintain consistency and precision. Ongoing assessment programs with continuous feedback and education are necessary to maintain quality care. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Nuchal Translucency Quality Review (NTQR) program: first one and half million results.

OBJECTIVE: To evaluate the performance of first-trimester nuchal translucency (NT) measurement by providers (physician-sonologists and sonographers) within the Nuchal Translucency Quality Review (NTQR) program. METHODS: After training and credentialing providers, the NTQR monitored performance of NT measurement by the extent to which an individual's median multiple of the normal median (MoM) for crown-rump length (CRL) was within the range 0.9-1.1 MoM of a published normal median curve. The SD of log10 MoM and regression slope of NT on CRL were also evaluated. We report the distribution between providers of these performance indicators and evaluate potential sources of variation. RESULTS: Among the first 1.5 million scans in the NTQR program, performed between 2005 and 2011, there were 1 485 944 with CRL in the range 41-84 mm, from 4710 providers at 2150 ultrasound units. Among the 3463 providers with at least 30 scans in total, the median of the providers' median NT-MoMs was 0.913. Only 1901 (55%) had a median NT-MoM within the expected range; there were 89 above 1.1 MoM, 1046 at 0.8-0.9 MoM, 344 at 0.7-0.8 MoM and 83 below 0.7 MoM. There was a small increase in the median NT-MoM according to providers' length of time in the NTQR program and number of scans entered annually. On average, physician-sonologists had a higher median NT-MoM than did sonographers, as did those already credentialed before joining the program. The median provider SD was 0.093 and the median slope was 13.5%. SD correlated negatively with the median NT-MoM (r = -0.34) and positively with the slope (r = 0.22). CONCLUSION: Even with extensive training, credentialing and monitoring, there remains considerable variability between NT providers. There was a general tendency towards under-measurement of NT compared with expected values, although more experienced providers had performance closer to that expected.

Fetal anatomic evaluation in the overweight and obese gravida.

OBJECTIVES: To evaluate the rate of completion of anatomic surveys of fetuses in overweight and obese gravid patients as compared with normal controls. METHODS: This was a retrospective review of anatomic ultrasound scans performed between 2004 and 2007. Women were stratified by prepregnancy body mass index (BMI) into normal weight (BMI, 18.5-24.9 kg/m(2)), overweight (BMI, 25.0-29.9 kg/m(2)) and obese Class I (BMI, 30.0-34.9 kg/m(2)), Class II (BMI, 35.0-39.9 kg/m(2)) and Class III (BMI >or= 40.0 kg/m(2)) groups. Rates of completion of basic and comprehensive scans, gestational age at completion and number of scans required were compared. RESULTS: For the 7140 patients included, completion rates for both the basic (normal weight, n = 2253 (79%); overweight, n = 1771 (76%); obese Class I, n = 767 (72%), Class II, n = 323 (61%) and Class III, n = 171 (49%)) and comprehensive (normal weight, n = 1234 (43%); overweight, n = 930 (40%); obese Class I, n = 404 (38%), Class II, n = 215 (41%) and Class III, n = 108 (31%)) surveys decreased significantly with increasing BMI (P < 0.00001). For surveys completed, the mean number of scans required was significantly higher for obese patients (basic: normal weight 1.3 vs. obese Class III 1.9; comprehensive: normal weight 1.7 vs. obese Class III, 2.2)(P < 0.00001). The overall completion rate improved at each gestational week, but was best between 20 and 23 weeks for obese patients. CONCLUSIONS: As maternal BMI increases, the rate of completion of anatomic surveys decreases and the number of scans required increases. Delaying the initial survey until 20 weeks' gestation may improve the capacity to complete the examination in a single visit. It should be noted that these results represent completion rates at a tertiary referral center, and therefore may not reflect community experience.

Fetal nuchal translucency thickness evaluation in the overweight and obese gravida.

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: This was a retrospective review of ultrasound examinations for NT measurement in 11-14-week singleton pregnancies performed at a single site from 2004 to 2007. Women were stratified by prepregnancy BMI into normal weight (BMI, 18.5-24.9 kg/m(2)), overweight (BMI, 25.0-29.9 kg/m(2)) and obese Class I (BMI, 30.0-34.9 kg/m(2)), Class II (BMI, 35.0-39.9 kg/m(2)) and Class III (BMI >or= 40.0 kg/m(2)) groups. The failure rate, the time required for measurement, and the total study time in min were evaluated by BMI class for the first attempt and for all attempts at NT measurement. RESULTS: A total of 2508 women underwent attempted NT screening with complete data available on 1678 women (1707 examinations). The failure rate for NT screening varied significantly according to BMI (P < 0.001). At the first attempt, the median time for NT measurement varied significantly according to 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: As maternal BMI increases, the time required to obtain NT measurements and the failure rate increase. Before the ultrasound examination, patients with a BMI over 30 should be counseled regarding the need for additional time and failure rates for first-trimester screening.

Sonographic birth-weight prediction in obese patients using the gestation-adjusted prediction method.

OBJECTIVES: Ultrasound birth-weight prediction may be more accurate if assessed at 34 to 36 + 6 weeks' gestation and extrapolated using the gestation-adjusted projection (GAP) method than if done at term. Because ultrasound is less accurate in women with elevated body mass index (BMI), we assessed the accuracy of GAP birth-weight prediction in obese as compared to non-obese women. METHODS: We performed a retrospective review of 1382 women with singleton pregnancies who had undergone fetal ultrasound examination at between 34 + 0 and 36 + 6 weeks, subclassified by pre-pregnancy BMI. Analysis of variance was used to compare predicted and actual birth weight. RESULTS: 1025 controls and 357 obese women were included. The obese women were divided by BMI: 159 in Class I (BMI, 30-34.9 kg/m(2)); 105 in Class II (BMI, 35-40 kg/m(2)) and 93 in Class III (BMI > 40 kg/m(2)). Mean systematic (percent) birth-weight prediction error was within 4% for all groups, with a 95% error range between - 5% and + 5%. The GAP method was able to predict actual birth weight within 20% for all groups in over 90% of cases. For all groups, the GAP method correctly excluded the presence of macrosomia with >or= 90% specificity. Negative likelihood ratios for the prediction of macrosomia were between 0.4 and 0.6 for all groups, regardless of obesity. CONCLUSIONS: The GAP method of birth-weight prediction using ultrasound measurement at 34 to 36 + 6 weeks predicts birth weight within 20% error in over 90% of cases, and is able to exclude macrosomia with over 90% accuracy regardless of maternal BMI.