Table 1.
Participant characteristics by fibroid status, Right from the Start, 2000–2012 (n = 4,622)
| Characteristic | Fibroids n = 475 |
No Fibroids n = 4,147 |
ORa | 95% CI | ||
|---|---|---|---|---|---|---|
| n | % | n | % | |||
| Maternal Age (years) | ||||||
| <25 | 42 | 8.8 | 868 | 20.9 | 1.00 | Referent |
| 25–29 | 120 | 25.3 | 1,531 | 36.9 | 1.62 | 1.13–2.32 |
| 30–34 | 197 | 41.5 | 1,294 | 31.2 | 3.15 | 2.23–4.44 |
| ≥ 35 | 116 | 24.4 | 454 | 10.9 | 5.28 | 3.64–7.65 |
| Race | ||||||
| White, non-Hispanic | 268 | 56.4 | 3,038 | 73.3 | 1.00 | Referent |
| Black, non-Hispanic | 156 | 32.8 | 650 | 15.7 | 2.72 | 2.19–3.37 |
| Hispanic | 25 | 5.3 | 286 | 6.9 | 0.99 | 0.65–1.52 |
| Other | 26 | 5.5 | 173 | 4.2 | 1.70 | 1.11–2.62 |
| Parity | ||||||
| Nulliparous | 223 | 46.9 | 1,890 | 45.6 | 1.00 | Referent |
| 1 | 153 | 32.3 | 1,367 | 33.0 | 0.95 | 0.76–1.18 |
| 2 + | 87 | 18.3 | 669 | 16.1 | 1.10 | 0.85–1.43 |
| Missing | 12 | 2.5 | 221 | 5.3 | ||
| History of SAB | ||||||
| No | 323 | 68.0 | 3,097 | 74.7 | 1.00 | Referent |
| Yes | 140 | 29.5 | 829 | 20.0 | 1.62 | 1.31–2.00 |
| Missing | 12 | 2.5 | 221 | 5.3 | ||
| History of Preterm Birth | ||||||
| No | 419 | 88.2 | 3,608 | 87.0 | 1.00 | Referent |
| Yes | 44 | 9.3 | 318 | 7.7 | 1.19 | 0.85–1.66 |
| Missing | 12 | 2.5 | 221 | 5.3 | ||
| Marital Status | ||||||
| Married | 421 | 88.6 | 3,702 | 89.3 | 1.00 | Referent |
| Other | 54 | 11.4 | 445 | 10.7 | 1.07 | 0.79–1.44 |
| BMIb | ||||||
| Underweight | 11 | 2.3 | 106 | 2.6 | 1.18 | 0.62–2.23 |
| Normal weight | 200 | 42.1 | 2,266 | 54.6 | 1.00 | Referent |
| Overweight | 134 | 28.2 | 945 | 22.8 | 1.61 | 1.28–2.03 |
| Obese | 127 | 26.7 | 772 | 18.6 | 1.86 | 1.47–2.36 |
| Missing | 3 | 0.6 | 58 | 1.4 | ||
| Education | ||||||
| High school or less | 57 | 12.0 | 735 | 17.7 | 1.00 | Referent |
| Some college | 84 | 17.7 | 759 | 18.3 | 1.43 | 1.00–2.03 |
| College or more | 334 | 70.3 | 2,653 | 64.0 | 1.62 | 1.21–2.18 |
| Annual Income ($) | ||||||
| ≤ 40,000 | 112 | 23.6 | 1,184 | 28.6 | 1.00 | Referent |
| 40,001 to < 80,000 | 176 | 37.1 | 1,468 | 35.4 | 1.27 | 0.99–1.63 |
| ≥ 80,000 | 166 | 34.9 | 1,175 | 28.3 | 1.49 | 1.16–1.92 |
| Missing | 21 | 4.4 | 320 | 7.7 | ||
| Smoking Statusc | ||||||
| Never smoker | 350 | 73.7 | 2,891 | 69.7 | 1.00 | Referent |
| Current | 34 | 7.2 | 488 | 11.8 | 0.58 | 0.40–0.83 |
| Former | 83 | 17.5 | 576 | 13.9 | 1.19 | 0.92–1.54 |
| Missing | 8 | 1.7 | 192 | 4.6 | ||
Abbreviations: OR Odds ratio, CI Confidence interval, SAB Spontaneous abortion, BMI Body mass index
a Crude odds of exposure given maternal characteristic
b BMI categories from Institute of Medicine guidelines: Underweight < 18.5, Normal weight 18.5–24.99, Overweight 25–29.99, Obese ≥ 30
c Former smoker defined as smoking cessation one month or more before last menstrual period