Table 4. Outcomes at 22-26 Months’ Corrected Age for Children Born at 22-26 Weeks’ Gestational Age in 2013-2016.
| Variables | No./total (%), by gestational age in weeksa | |||||
|---|---|---|---|---|---|---|
| 22 (n = 31) | 23 (n = 292) | 24 (n = 567) | 25 (n = 733) | 26 (n = 943) | 22-26 (n = 2566) | |
| Bayley-III scoresb | ||||||
| Cognitive composite score | ||||||
| No. evaluated | 31 | 285 | 559 | 712 | 905 | 2492 |
| Mean (SD) | 80.0 (16.4) | 79.7 (16.8) | 82.0 (15.7) | 86.3 (15.1) | 88.4 (14.6) | 85.3 (15.6) |
| Median (IQR) | 85 (65-90) | 80 (70-90) | 85 (70-95) | 90 (80-95) | 90 (80-95) | 85 (75-95) |
| <70 | 8 (25.8) | 68 (23.9) | 117 (20.9) | 89 (12.5) | 75 (8.3) | 357 (14.3) |
| 70-84 | 6 (19.4) | 82 (28.8) | 145 (25.9) | 163 (22.9) | 207 (22.9) | 603 (24.2) |
| ≥85 | 17 (54.8) | 135 (47.4) | 297 (53.1) | 460 (64.6) | 623 (68.8) | 1532 (61.5) |
| Language composite score | ||||||
| No. evaluated | 31 | 282 | 544 | 696 | 878 | 2431 |
| Mean (SD) | 78.6 (19.0) | 75.0 (17.8) | 77.6 (17.7) | 82.3 (17.4) | 84.4 (16.7) | 81.1 (17.6) |
| Median (IQR) | 79 (71-94) | 74 (62-89) | 79 (65-89) | 83 (71-94) | 86 (74-97) | 83 (71-94) |
| <70 | 7 (22.6) | 111 (39.4) | 177 (32.5) | 151 (21.7) | 161 (18.3) | 607 (25.0) |
| 70-84 | 11 (35.5) | 74 (26.2) | 155 (28.5) | 214 (30.7) | 241 (27.4) | 695 (28.6) |
| ≥85 | 13 (41.9) | 97 (34.4) | 212 (39.0) | 331 (47.6) | 476 (54.2) | 1129 (46.4) |
| Motor composite score | ||||||
| No. evaluated | 30 | 278 | 539 | 697 | 882 | 2426 |
| Mean (SD) | 76.6 (18.4) | 76.7 (17.8) | 80.2 (16.5) | 85.7 (15.5) | 88.6 (15.0) | 84.4 (16.4) |
| Median (IQR) | 84 (70-91) | 79 (64-88) | 82 (70-91) | 88 (79-97) | 91 (82-97) | 88 (76-94) |
| <70 | 7 (23.3) | 81 (29.1) | 123 (22.8) | 87 (12.5) | 85 (9.6) | 383 (15.8) |
| 70-84 | 8 (26.7) | 87 (31.3) | 151 (28.0) | 175 (25.1) | 181 (20.5) | 602 (24.8) |
| ≥85 | 15 (50.0) | 110 (39.6) | 265 (49.2) | 435 (62.4) | 616 (69.8) | 1441 (59.4) |
| Cerebral palsyc | ||||||
| None | 16/31 (51.6) | 197/290 (67.9) | 432/566 (76.3) | 627/730 (85.9) | 826/938 (88.1) | 2098/2555 (82.1) |
| Mild | 8/31 (25.8) | 41/290 (14.1) | 73/566 (12.9) | 56/730 (7.7) | 65/938 (6.9) | 243/2555 (9.5) |
| Moderate | 4/31 (12.9) | 27/290 (9.3) | 40/566 (7.1) | 24/730 (3.3) | 27/938 (2.9) | 122/2555 (4.8) |
| Severe | 3/31 (9.7) | 25/290 (8.6) | 21/566 (3.7) | 23/730 (3.2) | 20/938 (2.1) | 92/2555 (3.6) |
| GMFCS leveld | ||||||
| 0 | 12/31 (38.7) | 145/289 (50.2) | 336/565 (59.5) | 536/731 (73.3) | 731/937 (78.0) | 1760/2553 (68.9) |
| 1 | 11/31 (35.5) | 83/289 (28.7) | 151/565 (26.7) | 132/731 (18.1) | 146/937 (15.6) | 523/2553 (20.5) |
| 2 or 3 | 5/31 (16.1) | 39/289 (13.5) | 56/565 (9.9) | 39/731 (5.3) | 39/937 (4.2) | 178/2553 (7.0) |
| 4 or 5 | 3/31 (9.7) | 22/289 (7.6) | 22/565 (3.9) | 24/731 (3.3) | 21/937 (2.2) | 92/2553 (3.6) |
| Visione | ||||||
| Normal in both eyes | 22/31 (71.0) | 204/289 (70.6) | 460/566 (81.3) | 629/731 (86.0) | 856/938 (91.3) | 2171/2555 (85.0) |
| Corrective lenses/other abnormality but not blind in either eye | 5/31 (16.1) | 75/289 (26.0) | 94/566 (16.6) | 91/731 (12.4) | 74/938 (7.9) | 339/2555 (13.3) |
| Blind in 1 eye | 1/31 (3.2) | 2/289 (0.7) | 3/566 (0.5) | 1/731 (0.1) | 0/938 (0.0) | 7/2555 (0.3) |
| Blind in both eyes | 3/31 (9.7) | 8/289 (2.8) | 9/566 (1.6) | 10/731 (1.4) | 8/938 (0.9) | 38/2555 (1.5) |
| Hearingf | ||||||
| No functional impairment | 29/30 (96.7) | 271/285 (95.1) | 544/560 (97.1) | 707/724 (97.7) | 907/929 (97.6) | 2458/2528 (97.2) |
| Functional impairment | 1/30 (3.3) | 14/285 (4.9) | 16/560 (2.9) | 17/724 (2.3) | 22/929 (2.4) | 70/2528 (2.8) |
| Cochlear implant or aid | 0/30 (0.0) | 8/285 (2.8) | 13/561 (2.3) | 16/722 (2.2) | 27/929 (2.9) | 64/2527 (2.5) |
| Medical history and functional outcomes | ||||||
| Had a hospitalization after discharge | 20/31 (64.5) | 171/290 (59.0) | 311/567 (54.9) | 360/732 (49.2) | 415/941 (44.1) | 1277/2561 (49.9) |
| No. of hospitalizations, median (IQR) | 3 (2-4) | 2 (1-3) | 2 (1-3) | 2 (1-3) | 1 (1-3) | 2 (1-3) |
| Oral motor skills | ||||||
| Independently feeds self | 20/31 (64.5) | 208/290 (71.7) | 436/567 (76.9) | 622/732 (85.0) | 804/941 (85.4) | 2090/2561 (81.6) |
| Dependent oral feeding | 5/31 (16.1) | 30/290 (10.3) | 50/567 (8.8) | 45/732 (6.1) | 57/941 (6.1) | 187/2561 (7.3) |
| Limited oral feeding | 5/31 (16.1) | 38/290 (13.1) | 59/567 (10.4) | 51/732 (7.0) | 62/941 (6.6) | 215/2561 (8.4) |
| No oral feeding | 1/31 (3.2) | 14/290 (4.8) | 22/567 (3.9) | 14/732 (1.9) | 18/941 (1.9) | 69/2561 (2.7) |
| Current medical equipment | ||||||
| Apnea monitor | 0/31 (0.0) | 8/290 (2.8) | 9/567 (1.6) | 8/732 (1.1) | 14/941 (1.5) | 39/2561 (1.5) |
| Oxygen | 3/31 (9.7) | 33/290 (11.4) | 33/567 (5.8) | 36/732 (4.9) | 30/941 (3.2) | 135/2561 (5.3) |
| Ventilator or continuous positive airway pressure | 0/31 (0.0) | 9/290 (3.1) | 10/567 (1.8) | 14/732 (1.9) | 10/941 (1.1) | 43/2561 (1.7) |
| Gastrostomy or other tube feeding | 6/31 (19.4) | 52/290 (17.9) | 81/567 (14.3) | 75/732 (10.2) | 80/941 (8.5) | 294/2561 (11.5) |
| Tracheostomy | 1/31 (3.2) | 19/290 (6.6) | 29/567 (5.1) | 23/732 (3.1) | 22/941 (2.3) | 94/2561 (3.7) |
| Pulse oximeter | 3/31 (9.7) | 42/290 (14.5) | 57/567 (10.1) | 48/732 (6.6) | 41/941 (4.4) | 191/2561 (7.5) |
| Any (≥1) of above | 7/31 (22.6) | 71/290 (24.5) | 106/567 (18.7) | 99/732 (13.5) | 99/941 (10.5) | 382/2561 (14.9) |
| Multiple (≥2) of above | 3/31 (9.7) | 44/290 (15.2) | 58/567 (10.2) | 46/732 (6.3) | 41/941 (4.4) | 192/2561 (7.5) |
| Mobility aids/supportive equipment | ||||||
| Adapted stroller or wheelchair | 1/31 (3.2) | 16/290 (5.5) | 24/566 (4.2) | 17/732 (2.3) | 20/941 (2.1) | 78/2560 (3.0) |
| Braces/orthotics | 7/31 (22.6) | 60/290 (20.7) | 88/566 (15.5) | 80/732 (10.9) | 93/941 (9.9) | 328/2560 (12.8) |
| Walker | 4/31 (12.9) | 24/290 (8.3) | 23/566 (4.1) | 22/732 (3.0) | 21/941 (2.2) | 94/2560 (3.7) |
| Stander | 1/31 (3.2) | 10/290 (3.4) | 14/566 (2.5) | 19/732 (2.6) | 12/941 (1.3) | 56/2560 (2.2) |
| Corner chair or other adaptive seat | 1/31 (3.2) | 9/290 (3.1) | 7/566 (1.2) | 7/732 (1.0) | 5/941 (0.5) | 29/2560 (1.1) |
| Any (≥1) of above | 10/31 (32.3) | 77/290 (26.6) | 103/566 (18.2) | 91/732 (12.4) | 112/941 (11.9) | 393/2560 (15.4) |
| Multiple (≥2) of above | 3/31 (9.7) | 32/290 (11.0) | 32/566 (5.7) | 35/732 (4.8) | 29/941 (3.1) | 131/2560 (5.1) |
Abbreviations: Bayley-III, Bayley Scales of Infant and Toddler Development, Third Edition; GMFCS, Gross Motor Function Classification System.
Data are expressed as No./total (%) of children assessed at 22-26 months’ corrected age unless otherwise indicated. Corrected age represents age of child based on expected date of delivery, calculated by subtracting the number of weeks before 40 weeks of gestation at which birth occurred from chronological age.15 To minimize the number of comparisons, differences in Bayley-III composite scores by gestational age were tested for the mean scores only. Similarly, differences by gestational age were not examined for each item in the current medical equipment and mobility aids/supportive equipment groups, but “any of above” was compared across gestational ages. Vision data were analyzed as normal in both eyes vs the other categories combined. For the purpose of assessing whether the proportion of infants with a cochlear implant or hearing aid differed by gestational age, infants born at 22 and 23 weeks’ gestational age were combined. Differences by gestational age were significant for most outcomes; adjusted P < .001 except for adjusted P = .12 for hearing impairment, adjusted P = .93 for cochlear implant or hearing aid, and adjusted P = .29 for median number of hospitalizations after discharge, adjusting for study center, small for gestational age, male sex, multiple gestation, maternal race and ethnicity (Black, Hispanic, White, or other), and maternal education assessed at the time of delivery (less than high school degree, high school degree, more than high school degree, or unknown).
Each Bayley-III composite score is standardized to a mean of 100 (SD, 15).The cognitive composite score range is 55 to 145, the language composite score range is 47 to 153, and the motor composite score range is 46 to 154, with lower scores representing more impaired outcomes.
Mild cerebral palsy was defined as GMFCS level 1, moderate cerebral palsy as GMFCS level 2 or 3, and severe cerebral palsy as GMFCS level 4 or 5.25
The GMFCS levels are defined as follows: level 0, walks independently, with normal and fluent gait; level 1, walks 10 steps independently, but with some gait abnormalities; level 2, maintains floor sitting but may need to use hands for support to maintain balance, creeps on stomach or crawls on hands and knees with reciprocal leg movement, may pull to stand and take steps holding onto furniture; level 3, maintains floor sitting when the low back is supported, rolls and creeps forward on stomach or may crawl with or without reciprocal leg movements; level 4, has head control but trunk support is required for floor sitting, can roll to supine, may roll to prone; and level 5, is unable to maintain antigravity head and trunk postures in prone and sitting positions, requires adult assistance to roll. Higher levels indicate greater limitation.
Vision in each eye was recorded as normal, having been prescribed corrective lenses, other abnormality, blind (consistent with refraction of 20/200 or less) with some functional vision, or no useful vision.
No functional hearing impairment was defined as being able to follow oral directions given during the assessment, with or without amplification. Functional hearing impairment was defined as permanent hearing loss that did not permit a child to understand directions and communicate, with or without amplification.