Maternal characteristics by gestational age among singleton births in California
| Variable | Full term (≥37 weeks, n=457) | All preterm (<37 weeks, n=411) | Late preterm (32–36 weeks, n=249) | Early preterm (20–31 weeks, n=162) |
| Maternal age, mean (SD) in years | 29.9 (6.0) | 29.5 (6.2) | 29.6 (6.2) | 29.4 (6.4) |
| Race/ethnicity, n (%) | ||||
| White | 157 (34) | 140 (34) | 86 (34) | 54 (33) |
| Black | 6 (1) | 10 (2) | 5 (2) | 5 (3) |
| Hispanic | 205 (45) | 176 (43) | 109 (44) | 67 (41) |
| Asian | 69 (15) | 61 (15) | 40 (16) | 21 (13) |
| Other | 20 (4) | 24 (6) | 9 (4) | 15 (9) |
| Smoking status, n (%) | ||||
| No | 450 (98) | 400 (97) | 245 (98) | 155 (96) |
| Yes | 7 (2) | 11 (3) | 4 (2) | 7 (4) |
| Hypertension, n (%) | ||||
| None | 437 (96) | 323 (79) | 204 (82) | 119 (73) |
| Chronic hypertension | 6 (1) | 12 (3) | 3 (1) | 9 (6) |
| Gestational hypertension | 7 (2) | 9 (2) | 7 (3) | 2 (1) |
| Pre-eclampsia | 7 (2) | 67 (16) | 35 (14) | 32 (20) |
| Diabetes, n (%) | ||||
| No | 451 (99) | 392 (95) | 238 (96) | 154 (95) |
| Yes | 6 (1) | 19 (5) | 11 (4) | 8 (5) |
| Weight by BMI in kg/m2, n (%) | ||||
| Underweight (<18.5) | 26 (6) | 20 (5) | 9 (4) | 11 (7) |
| Normal (18.5–24.9) | 250 (55) | 213 (52) | 138 (55) | 75 (46) |
| Overweight (25–29.9) | 107 (23) | 90 (22) | 49 (20) | 41 (25) |
| Obese (≥30) | 74 (16) | 88 (21) | 53 (60) | 35 (22) |
| Cholesterol, mean (SD) in mg/dL | ||||
| Total | 224 (39) | 228 (41) | 227 (38) | 230 (45) |
| LDL | 116 (34) | 111 (34) | 109 (32) | 113 (37) |
| HDL | 73 (17) | 76 (17) | 76 (17) | 76 (17) |
| Triglycerides | 202 (67) | 204 (77) | 204 (77) | 205 (76) |
BMI, body mass index; HDL, high-density lipoprotein; LDL, low-density lipoprotein.