Table 2. Chromosomal and Pregnancy Outcomes by Nuchal Translucency Measurementa.
| Outcome | All pregnancies | Nuchal translucency measurement, mm | ||||||
|---|---|---|---|---|---|---|---|---|
| <2.0 | 2.0 to <2.5 | 2.5 to <3.0 | 3.0 to <3.5 | 3.5 to <5.0 | 5.0 to <6.5 | ≥6.5 | ||
| No. of cytogenetic testing results | 15 755 | 11 552 | 1875 | 653 | 421 | 602 | 287 | 365 |
| Unknown result | 217 (1.4) | 180 (1.6) | 22 (1.2) | <6 (NA) | <6 (NA) | <6 (NA) | <6 (NA) | <6 (NA) |
| No chromosomal anomaly identified | 12 106 (76.8) | 9459 (81.9) | 1397 (74.5) | 450 (68.9) | 241 (57.2) | 341 (56.6) | 112 (39.0) | 106 (29.0) |
| Chromosomal anomaly | 3432 (21.8) | 1913 (16.6) | 456 (24.3) | 198 (30.3) | 179 (42.5) | 256 (42.5) | 174 (60.6) | 256 (70.1) |
| Identifiable on cfDNA screeningb,c | 1690 (49.2) | 543 (28.4) | 241 (52.9) | 154 (77.8) | 149 (83.2) | 215 (84.0) | 153 (87.9) | 235 (91.8) |
| Not identifiable on cfDNA screeningb,d | 1742 (50.8) | 1370 (71.6) | 215 (47.1) | 44 (22.2) | 30 (16.8) | 41 (16.0) | 21 (12.1) | 21 (8.2) |
| No. of cfDNA screening results for pregnancies without cytogenetic testing results | 38 754 | 30 551 | 5310 | 1701 | 667 | 398 | 69 | 58 |
| Unknown or uninformative result | 495 (1.3) | 404 (1.3) | 58 (1.1) | 14 (0.8) | <6 (NA) | 8 (2.0) | <6 (NA) | <6 (NA) |
| Low-risk result | 38 041 (98.2) | 30 071 (98.4) | 5234 (98.6) | 1674 (98.4) | 645 (96.7) | 354 (88.9) | 44 (63.8) | 19 (32.8) |
| High-risk result | 218 (0.6) | 76 (0.2) | 18 (0.3) | 13 (0.8) | 18 (2.7) | 36 (9.0) | 21 (30.4) | 36 (62.1) |
| No. of pregnancy outcomes with neither cytogenetic testing nor cfDNA screening results | 359 759 | 317 704 | 36 034 | 5120 | 701 | 88 | 48 | 64 |
| Lost to follow-up | 10 761 (3.0) | 9281 (2.9) | 1132 (3.1) | 181 (3.5) | 42 (6.0) | 38 (43.2) | 39 (81.3) | 48 (75.0) |
| Live birth | 347 190 (96.5) | 306 838 (96.6) | 34 727 (96.4) | 4901 (95.7) | 655 (93.4) | 49 (55.7) | 7 (14.6) | 13 (20.3) |
| Clinical findings at birthe | 15 552 (4.5) | 13 919 (4.5) | 1391 (4.0) | 203 (4.1) | 33 (5.0) | <6 (NA) | <6 (NA) | <6 (NA) |
| Pregnancy loss, termination, or stillbirth | 1808 (0.5) | 1585 (0.5) | 175 (0.5) | 38 (0.7) | <6 (NA) | <6 (NA) | <6 (NA) | <6 (NA) |
| No. of pregnancies with chromosomal anomalies | 414 268 | 359 807 | 43 219 | 7474 | 1789 | 1088 | 404 | 487 |
| No chromosomal anomaly identifiedf | 382 478 (92.3) | 332 945 (92.5) | 40 046 (92.7) | 6846 (91.6) | 1522 (85.1) | 771 (70.9) | 179 (44.3) | 169 (34.7) |
| Chromosomal anomalyg | 3432 (0.8) | 1913 (0.5) | 456 (1.1) | 198 (2.6) | 179 (10.0) | 256 (23.5) | 174 (43.1) | 256 (52.6) |
| Excluded | 28 358 (6.8) | 24 949 (6.9) | 2717 (6.3) | 430 (5.8) | 88 (4.9) | 61 (5.6) | 51 (12.6) | 62 (12.7) |
| Lost to follow-up | 10 761 (2.6) | 9281 (2.6) | 1132 (2.6) | 181 (2.4) | 42 (2.3) | 38 (3.5) | 39 (9.7) | 48 (9.9) |
| Excluded for other reasonh | 17 597 (4.2) | 15 668 (4.4) | 1585 (3.7) | 249 (3.3) | 46 (2.6) | 23 (2.1) | 12 (3.0) | 14 (2.9) |
Abbreviations: cfDNA, cell-free DNA; NA, not applicable.
Unless otherwise indicated, data are expressed as No. (%) of patients.
Includes those with choromosomal anomaly identified.
Includes trisomies 21, 18, and 13 and sex chromosome aneuploidies.
Includes all other chromosomal anomalies, including other autosomal aneuploidies, mosaic aneuploidies, copy number variants. A detailed list of all chromosomal anomalies is available in eTable 2 in Supplement 1.
Includes any congenital structural anomaly identified among live births.
Indicates normal cytogenetic results or no cytogenetic results but low risk cfDNA results or no follow-up testing results but documented live birth with no clinical findings on examination.
Based on cytogenetic testing results.
Includes pregnancy loss, stillbirth, termination, live birth with clinical findings, or a high-risk cfDNA screening result.