Table 1.
Selected maternal and pregnancy characteristics by study eligibility and inclusion status among livebirths: California Statewide Expanded Alpha Fetoprotein Prenatal Screening Program, April–December 2007
| Total sample (n = 420 544) |
Analytic samplea (n = 164 158) |
|
|---|---|---|
| Race/ethnicity | ||
| Black, non-Hispanic | 6.1 | 5.7 |
| White, non-Hispanic | 27.2 | 26.4 |
| Hispanic | 53.5 | 53.5 |
| Asian, non-Hispanic | 12.8 | 14.0 |
| Other, non-Hispanic | 0.4 | 0.4 |
| Maternal age (years) | ||
| <20 | 9.7 | 7.9 |
| 20–24 | 22.8 | 21.2 |
| 25–34 | 50.6 | 56.3 |
| ≥35 | 16.9 | 14.6 |
| Maternal education (highest year completed) | ||
| <12 | 27.9 | 24.9 |
| 12 | 27.5 | 27.1 |
| 13–15 | 21.9 | 23.5 |
| ≥16 | 22.8 | 24.6 |
| Delivery insurance | ||
| Public | 49.5 | 43.2 |
| Private | 45.8 | 53.2 |
| Other/none | 4.7 | 3.6 |
| Prepregnancy BMI | ||
| Underweight (<18.5 kg/m2) | 3.8 | 3.8 |
| Normal (18.5–24.9 kg/m2) | 45.0 | 45.3 |
| Overweight (25.0–29.9 kg/m2) | 22.4 | 23.1 |
| Obese (≥30.0 kg/m2) | 16.8 | 18.0 |
| Missing | 12.0 | 9.9 |
| Parity | ||
| 0 | 39.8 | 40.8 |
| 1 | 31.1 | 31.9 |
| ≥2 | 29.1 | 27.3 |
| Smoking during pregnancy | ||
| None | 97.3 | 98.1 |
| Any | 2.7 | 1.9 |
| Birthweight (g) | ||
| <1500 | 0.9 | 0.9 |
| 1500–2499 | 4.4 | 4.2 |
| 2500–4499 | 93.5 | 93.7 |
| ≥4500 | 1.2 | 1.2 |
| Obstetric-based gestational age (weeks) | ||
| <37 | 7.4 | 7.1 |
| 37–41 | 91.8 | 92.2 |
| 42–44 | 0.7 | 0.7 |
| >44 | <0.1 | <0.1 |
a
Subjects were excluded if records indicated multiple birth, mother-pregnancy was not linked to Expanded Alpha-Fetoprotein Prenatal Screening Program (XAFP) record, birth certificate was missing obstetric estimate or early ultrasound was not recorded in the XAFP record, or ultrasound was conducted after 20 weeks.