Table 1.
Maternal and urine sample characteristics in the overall TIDES study sample and by study site.
| Characteristic | Overall n = 741 |
UCSF n = 196 |
UMN n = 204 |
URMC n = 209 |
UW N = 132 |
|---|---|---|---|---|---|
| Maternal age (years), mean (SD) | 30.5 (5.5) | 34.2 (4.1) | 30.7 (4.5) | 26.4 (5.5) | 31.4 (4.6) |
| Missing | 1 | 0 | 1 | 0 | 0 |
| Maternal race, n (%) | |||||
| White | 499 (67) | 137 (70) | 161 (79) | 99 (47) | 102 (77) |
| Black | 100 (14) | 6 (3) | 14 (7) | 74 (35) | 6 (6) |
| Asian | 52 (7) | 31 (16) | 9 (4) | 2 (1) | 10 (10) |
| Other, unknown, or multiple race(s) | 89 (12) | 22 (11) | 19 (9) | 24 (11) | 14 (14) |
| Missing | 1 | 0 | 1 | 0 | 0 |
| Maternal Hispanic or Latina ethnicity, n (%) | 67 (9) | 24 (12) | 6 (3) | 28 (13) | 9 (7) |
| Missing | 9 | 0 | 6 | 1 | 2 |
| Maternal highest educational attainment, n (%) | |||||
| High school or less | 105 (14) | 6 (3) | 9 (5) | 86 (41) | 4 (3) |
| Any college/technical schoola | 318 (43) | 76 (39) | 90 (45) | 93 (44) | 59 (45) |
| Any Graduate work | 312 (42) | 114 (58) | 101 (51) | 30 (14) | 67 (52) |
| Missing | 6 | 0 | 4 | 0 | 2 |
| Maternal height (cm), mean (SD) | 164.8 (7.3) | 164.9 (6.5) | 166.2 (7.6) | 162.6 (6.6) | 166.2 (8.0) |
| Missing | 3 | 0 | 1 | 0 | 2 |
| Maternal weight (kg), mean (SD) | 69.6 (17.6) | 65.3 (13.4) | 68.9 (15.3) | 75.3 (22.1) | 68.1 (15.8) |
| Missing | 8 | 0 | 4 | 1 | 3 |
| Pre-pregnancy body mass index (kg/m2), mean (SD) | 25.6 (6.3) | 24.0 (4.7) | 24.9 (5.1) | 28.5 (7.9) | 24.7 (5.6) |
| Missing | 8 | 0 | 4 | 1 | 3 |
| Parity, n (%) | |||||
| Primiparous or multiparous | 316 (45) | 79 (43) | 85 (43) | 102 (53) | 50 (42) |
| Missing | 43 | 11 | 4 | 15 | 13 |
| Pre-eclampsia/gestational hypertension, n (%)b | 102 (14) | 14 (8) | 30 (15) | 42 (20) | 16 (12) |
| Missing | 27 | 25 | 1 | 1 | 0 |
| Preterm deliveryc, n (%) | 59 (8) | 12 (6) | 19 (9) | 23 (11) | 5 (4) |
| Gestational age at sample collection (weeks), mean (SD) | 32.6 (2.9) | 32.4 (2.2) | 31.8 (2.1) | 31.2 (2.6) | 36.5 (2.2) |
| Urinary creatinine concentration (mg/dL), mean (SD) | 92.8 (66.4) | 76.0 (58.1) | 87.5 (65.1) | 123.1 (72.6) | 78.1 (52.5) |
| Urinary specific gravity, mean (SD) | 1.015 (0.007) | 1.013 (0.007) | 1.014 (0.007) | 1.018 (0.007) | 1.014 (0.007) |
Abbreviations: cm = centimeter; dL = deciliter; kg = kilogram; m = meter; mg = milligram; UCSF = University of California, San Francisco; UMN = University of Minnesota; URMC = University of Rochester Medical Center; UW = University of Washington
a
Up to Bachelor’s degree
b
Based on medical chart review and International Classification of Diseases 9th or 10th edition codes
c
< 37 weeks completed gestation