TABLE 1.
Baseline demographic and delivery characteristics of cases who developed spontaneous preterm birth and controls1
| Variable | Cases (n = 16) | Controls (n = 32) | P value |
|---|---|---|---|
| Baseline demographic characteristics | |||
| Age, y | 28.88 ± 4.92 | 28.38 ± 5.77 | 0.756 |
| Black | 9 (56.25) | 18 (56.25) | 1.00 |
| White | 5 (31.25) | 10 (31.25) | |
| Asian | 2 (12.5) | 4 (12.5) | |
| Private insurance | 10 (62.5) | 23 (71.9) | 0.527 |
| Medicaid | 6 (37.5) | 9 (28.1) | |
| First clinic BMI, kg/m2 | 27.93 ± 6.32 | 27.82 ± 5.76 | 0.957 |
| Normal or underweight | 4 (25.00) | 17 (53.13) | 0.149 |
| Overweight | 6 (37.51) | 3 (9.38) | |
| Obese | 6 (37.51) | 12 (37.50) | |
| Antibiotics within 8 wk before enrollment | 2 (12.5) | 3 (9.4) | 0.738 |
| Smoking within 8 wk before enrollment | 1 (6.3) | 0 (0) | 0.153 |
| Assisted reproduction therapy | 1 (6.3) | 3 (9.4) | 0.712 |
| First-trimester vaginal bleeding | 2 (12.5) | 4 (12.5) | 1.00 |
| Second-trimester vaginal bleeding | 1 (6.3) | 0 (0) | 0.153 |
| Delivery characteristics | |||
| Gestational weight gain, kg | 8.89 ± 5.44 | 13.29 ± 6.19 | 0.017 |
| Gestational weight gain, kg/gestational age | 0.265 ± 0.147 | 0.339 ± 0.157 | 0.122 |
| Gestational age at delivery, wk | 33.13 ± 3.77 | 39.44 ± 1.22 | <0.0001 |
1Values are mean ± SD for continuous variables and the P value is based on the t test; values are n (%) for categorical variables and the P value is based on the chi-square test.