Baseline Characteristics of Cohort (n=4,905)
| Gestational Age of 370/7-376/7 Weeks | Gestational Age of 380/7-386/7 Weeks | Gestational Age of 390/7-396/7 Weeks | Gestational Age of 400/7-406/7 Weeks | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Variable | Planned Delivery, n=177 | Expectant Management, n=4,728 | P | Planned Delivery, n=392 | Expectant Management, n=3,736 | P | Planned Delivery, n=534 | Expectant Management, n=2,434 | P | Planned Delivery, n=458 | Expectant Management, n=1,218 | P |
| Age, years | 0.36 | 0.21 | 0.23 | 0.06 | ||||||||
| ≤17 | 3 (1.7) | 170 (3.6) | 8 (2.0) | 135 (3.6) | 23 (4.3) | 86 (3.5) | 13 (2.8) | 40 (3.3) | ||||
| 18-25 | 76 (42.9) | 2,033 (43.0) | 160 (40.8) | 1,617 (43.3) | 206 (38.6) | 1,053 (43.3) | 179 (39.1) | 558 (45.8) | ||||
| 26-35 | 87 (49.2) | 2,322 (49.1) | 203 (51.8) | 1,822 (48.8) | 279 (52.2) | 1,190 (48.9) | 241 (52.6) | 572 (47.0) | ||||
| ≥36 | 11 (6.2) | 203 (4.3) | 21 (5.4) | 162 (4.3) | 26 (4.9) | 105 (4.3) | 25 (5.5) | 48 (3.9) | ||||
| Race | 0.94 | 0.24 | 0.93 | 0.09 | ||||||||
| White | 158 (89.3) | 4,212 (89.1) | 358 (91.3) | 3,340 (89.4) | 482 (90.3) | 2,194 (90.1) | 424 (92.6) | 1,094 (89.8) | ||||
| Black | 19 (10.7) | 516 (10.9) | 34 (8.7) | 396 (10.6) | 52 (9.7) | 240 (9.9) | 34 (7.4) | 124 (10.2) | ||||
| Nulliparous | 144/176 (81.8) | 4,224/4,713 (89.6) | <0.01 | 331/390 (84.9) | 3,362/3,724 (90.3) | <0.01 | 472/532 (88.7) | 2,196/2,427 (90.5) | 0.22 | 410/455 (90.1) | 1,096/1,215 (90.2) | 0.95 |
| WIC program | 68 (38.4) | 1,528 (32.3) | 0.09 | 127 (32.4) | 1,204 (32.2) | 0.98 | 161/533 (30.2) | 799/2,423 (33.0) | 0.22 | 113/455 (24.8) | 433/1,214 (35.7) | <0.01 |
| Married | 38 (21.5) | 1,122 (23.7) | 0.49 | 90 (23.0) | 877 (23.5) | 0.81 | 101 (18.9) | 571 (23.5) | 0.02 | 89 (19.4) | 300 (24.6) | 0.03 |
| Body mass index | n=171 | n=4,549 | <0.01 | n=378 | n=3,589 | <0.01 | n=518 | n=2,331 | <0.01 | n=440 | n=1,168 | 0.12 |
| Underweight | 7 (4.1) | 172 (3.8) | 6 (1.6) | 136 (3.8) | 21 (4.1) | 85 (3.7) | 10 (2.3) | 52 (4.5) | ||||
| Normal weight | 49 (28.7) | 1,858 (40.8) | 130 (34.4) | 1,473 (41.0) | 187 (36.1) | 965 (41.4) | 169 (38.4) | 476 (40.8) | ||||
| Overweight | 43 (25.2) | 1,055 (23.2) | 97 (25.7) | 835 (23.3) | 108 (20.9) | 551 (23.6) | 110 (25.0) | 283 (24.2) | ||||
| Obese | 72 (42.1) | 1,464 (32.2) | 145 (38.4) | 1,145 (31.9) | 202 (39.0) | 730 (31.3) | 151 (34.3) | 357 (30.6) | ||||
| Gestational weight gain, lb, mean ± SD | 30.9 ± 14.5(n=170) | 30.4 ± 15.0(n=4,561) | 0.68 | 28.3 ± 15.5(n=379) | 30.6 ± 15.0(n=3,601) | <0.01 | 30.0 ± 15.7(n=521) | 30.5 ± 14.8(n=2,344) | 0.49 | 30.3 ± 15.4 | 31.0 ± 14.8 | 0.42 |
| Tobacco use | 21/176 (11.9) | 749/4,706 (15.9) | 0.16 | 60 (15.3) | 588 (15.7) | 0.81 | 65/531 (12.2) | 412/2,423 (17.0) | <0.01 | 70/454 (15.4) | 207/1,214 (17.1) | 0.43 |
| Chronic medical illness | 8 (4.5) | 176 (3.7) | 0.58 | 19 (4.9) | 131 (3.5) | 0.18 | 21 (3.9) | 83 (3.4) | 0.55 | 18 (3.9) | 35 (2.9) | 0.27 |
| Prenatal care | n=172 | n=4,575 | <0.01 | n=379 | n=3,615 | <0.01 | n=520 | n=2,346 | <0.01 | n=435 | n=1,180 | <0.01 |
| Inadequate | 9 (5.2) | 251 (5.5) | 14 (3.7) | 199 (5.5) | 26 (5.0) | 137 (5.8) | 20 (4.6) | 76 (6.4) | ||||
| Intermediate adequate | 5 (2.9) | 340 (7.4) | 6 (1.6) | 320 (8.8) | 14 (2.7) | 274 (11.7) | 35 (8.1) | 178 (15.1) | ||||
| Adequate | 29 (16.9) | 2,005 (43.8) | 146 (38.5) | 1,688 (46.7) | 211 (40.6) | 1,179 (50.3) | 205 (47.1) | 646 (54.8) | ||||
| Adequate plusa | 129 (75.0) | 1,979 (43.3) | 213 (56.2) | 1,408 (39.0) | 269 (51.7) | 756 (32.2) | 175 (40.2) | 280 (23.7) | ||||
Notes: Data are presented as n (%) unless otherwise noted. For variables with missing data, the number of available data points is shown.
↵aAdequate plus prenatal care is defined as ≥110% of expected visits.9
WIC, Women-Infants-Children.