Table 1. Characteristics of pregnant women at enrollment and their infants at birth in the High-Risk Aspirin Study (1991-1996).
| Total N=792 | Non-SGA n=689 | SGA n=103 | P | |
|---|---|---|---|---|
| Mothers | ||||
| Race | ||||
| Non-Hispanic White | 243 (30.7) | 216 (31.4) | 27 (26.2) | 0.30 |
| Non-Hispanic Black | 493 (62.5) | 422 (61.3) | 71 (68.9) | |
| Other* | 56 (7.1) | 51 (7.4) | 5 (4.9) | |
| Maternal age (years)† | ||||
| <20 | 96 (12.1) | 83 (12.1) | 13 (12.6) | 0.76 |
| 20-29 | 444 (56.1) | 384 (55.7) | 60 (58.3) | |
| >=30 | 246 (31.1) | 216 (31.4) | 30 (29.1) | |
| Parity | ||||
| Nulliparous | 175 (22.1) | 538 (78.1) | 79 (76.7) | 0.75 |
| Parous | 617 (77.9) | 151 (21.9) | 24 (23.3) | |
| Marital status | ||||
| Married | 289 (36.5) | 433 (62.8) | 70 (68.0) | 0.31 |
| Not married | 503 (63.5) | 256 (37.2) | 33 (32.0) | |
| Smoking at study entry | ||||
| Smoker | 133 (16.8) | 582 (84.5) | 77 (74.8) | 0.01 |
| Nonsmoker | 659 (83.2) | 107 (15.5) | 26 (25.2) | |
| Prepregnancy BMI (kg/m2) | ||||
| <25 | 259 (32.7) | 224 (32.5) | 35 (34.0) | 0.33 |
| 25-29.9 | 185 (23.4) | 155 (22.5) | 30 (29.1) | |
| 30-34.9 | 155 (19.6) | 140 (20.3) | 15 (14.6) | |
| ≥35 | 193 (24.4) | 170 (24.7) | 23 (22.3) | |
| Education† | ||||
| < High school | 217 (27.4) | 195 (28.3) | 22 (21.4) | 0.02 |
| High school graduate | 356 (45.0) | 301 (43.7) | 55 (53.4) | |
| Some college | 160 (20.2) | 144 (20.9) | 16 (15.5) | |
| College graduate | 58 (7.3) | 49 (7.11) | 9 (8.74) | |
| Gestational age at enrollment, weeks‡ | 19.5 ± 3.9 | 19.6 ± 4.0 | 19.4 ± 3.9 | 0.61 |
| Season of blood sampling | ||||
| Winter (December-February) | 186 (23.5) | 162 (23.5) | 24 (23.3) | 1.00 |
| Spring (March-May) | 202 (25.5) | 175 (25.4) | 27 (26.2) | |
| Summer (June-August) | 185 (23.4) | 161 (23.4) | 24 (23.3) | |
| Fall (September-November) | 219 (27.7) | 191 (27.7) | 28 (27.2) | |
| Latitude of study site | ||||
| ≥40 degrees North | 173 (21.8) | 149 (21.6) | 24 (23.3 | 0.89 |
| 37-39 degrees North | 133 (16.8) | 115 (16.7) | 18 (17.5) | |
| 35-36 degrees North | 281 (35.5) | 248 (36.0) | 33 (32.0) | |
| ≤35 degrees North | 205 (25.9) | 177 (25.7) | 28 (27.2) | |
| Risk group in Aspirin trial | 0.21 | |||
| Prepregnancy diabetes | 184 (23.2) | 167 (24.2) | 17 (16.5) | |
| Chronic Hypertension | 322 (40.7) | 275 (39.9) | 47 (45.6) | |
| Previous preeclampsia | 286 (36.1) | 247 (35.9) | 39 (37.9) | |
| Infants | ||||
| Birth weight, g | 3143 ± 723 | 3284 ± 636 | 2203 ± 549 | <0.01 |
| Length, cm | 49.2 ± 4.0 | 49.8 ± 3.6 | 45.5 ± 4.5 | <0.01 |
| Head circumference, cm | 33.7 ± 2.4 | 34.0 ± 2.2 | 31.3 ± 2.5 | <0.01 |
| Infant sex | <0.01 | |||
| Male | 417 (52.7) | 377 (54.7) | 40 (38.8) | |
| Female | 375 (47.4) | 312 (45.3) | 63 (61.2) | |
| Gestational age at birth, weeks | 37.5 ± 2.6 | 37.7 ± 2.5 | 36.6 ± 3.1 | <0.01 |
| Preterm (<37 weeks) | 208 (26.3) | 166 (24.1) | 42 (40.8) | <0.01 |
| Term (≥37 weeks) | 584 (73.7) | 523 (75.9) | 61 (59.2) | |
| Low birth weight status | <0.01 | |||
| <2500 g | 128 (16.2) | 62 (9.0) | 66 (64.1) | |
| ≥2500 g | 664 (83.8) | 627 (91.0) | 37 (35.9) | |
Data are n(%) or mean±standard deviation unless otherwise specified.
SGA, small-for-gestational-age; BMI, body mass index.
*
n=53 Hispanic white, n=1 Hispanic black, n=2 American Indian/Alaskan
†
Six missing values for age; one missing value for education.
‡
range 12-26 weeks.