The Value of Repeated Evaluation After Initial Failed Nuchal Translucency Measurement

OBJECTIVE: The purpose of this study was to assess the value of reattempting the nuchal translucency (NT) measurement after an initial failure. METHODS: Women undergoing NT measurements by NT-certified sonographers within a combined screening program over an 18-month period were categorized as "desiring" screening (all women), "eligible" (live fetus with crown-rump length of 45-84 mm), and "defaulters" (failed to keep a visit after a failed NT measurement attempt). If the NT measurement was unobtainable, patients with live fetuses and a crown-rump length of less than 84 mm were offered reexamination. RESULTS: Nuchal translucency measurement success rates at the initial visit for those desiring (n = 837) and eligible (n = 767) were 73.3% and 80.0%, respectively. Composite NT measurement success rates for up to 3 visits were significantly greater than for only 1 visit for those desiring screening (84.8%; P < .0001), eligible for screening (86.6%; P = .0004), and not defaulting on follow-up (97.0%; P < .0001). The screen-positive rates were similar for 1 and up to 3 visits (10.4% and 11.0%). One additional (16.6%) aneuploidy was detected through a second visit. CONCLUSIONS: Reattempting NT measurements significantly increases the overall NT measurement success rate and detects additional aneuploidies at constant screen-positive and invasive prenatal diagnosis rates.