TABLE 1—
Independent Variables Among 10 400 US-Born Black and White Women in California Who Gave Birth During 2003–2010
| Variable | Source | Description or Categories |
| Maternal race, ethnicity, nativity (first listed race, ethnicity, and maternal birthplace) | Birth certificate | The sample for this study consisted of women surveyed in MIHA who were Black or White, were not Latina, and were US-born. |
| Socioeconomic characteristics | ||
| Family income | MIHA | Total pretax income from all sources during the calendar year before the birth, categorized in relation to the respondent’s family sizea |
| Maternal educational attainment | MIHA (or birth certificate if MIHA data were missing) | Less than high school, high-school graduate or GED, some college, or college graduate |
| Paternal educational attainment | Birth certificate | Less than high school, high-school graduate or GED, some college, or college graduate |
| Mother’s parents’ educational attainment | MIHA | Highest educational attainment of the respondent’s most-educated parent she lived with around age 13: less than high school, high-school graduate or GED, some college, or college graduate |
| Maternal occupation | Birth certificate | Categorized with Bureau of Labor Statistics job classesb |
| Paternal occupation | Birth certificate | Categorized with Bureau of Labor Statistics job classesb |
| Health insurance coverage before and during pregnancy | MIHA | Private insurance vs uninsured or any other coverage |
| Census tract–level (neighborhood) poverty | Respondent’s geocoded residential address from the birth certificate, linked with information from the 2005–2009 American Community Survey | The percentage of census-tract residents with household incomes below the FPLc |
| Sociodemographic characteristics | ||
| Maternal age | Birth certificate | 15–19, 20–34, or ≥ 35 y |
| Paternal age | Birth certificate | 15–19, 20–34, or ≥ 35 y |
| Parity (total live births including index birth) | Birth certificate | Primiparous, 2–4 births, or ≥ 5 births |
| Prenatal care | ||
| Trimester of prenatal care initiation | MIHA | First, second, or third trimester or no prenatal care; excluding visits just for a pregnancy test |
| Inadequate number of prenatal visits | Birth certificate | Based on the Kotelchuck index69; received < 50% or ≥ 50% of expected prenatal visits based on gestational age at delivery |
| Health-related attitudes or behaviors | ||
| Smoking during pregnancy | MIHA | Any smoking or none |
| Drinking alcohol during pregnancy | MIHA | Any alcohol use during pregnancy or none |
| Pregnancy intendedness | MIHA | Pregnancy was unintended (wanted to be pregnant later or never) or intended |
| Stressors during the index pregnancy | ||
| Intimate partner violence | MIHA | Experienced physical violence from a partner or spouse |
| Homelessness | MIHA | Homeless at some point |
| Job loss | MIHA | Lost her job despite wanting to continue working |
| Partner job loss | MIHA | Partner or spouse lost job |
| Separation or divorce | MIHA | Separated or divorced during pregnancy |
| Moving | MIHA | Moved during pregnancy |
| Bills | MIHA | Had a lot of bills that were hard to pay |
| Incarceration | MIHA | Respondent or her partner went to jail at some point during the pregnancy |
| Drug or alcohol problem | MIHA | Someone close to the respondent had a serious drug or alcohol problem |
| Food insecurity, measured with USDA 6-item instrument | MIHA | No food insecurity, food insecurity without hunger, or food insecurity with hunger |
| Social support during the index pregnancy | ||
| Marital status | MIHA | Married, living with a partner, or single, separated, divorced, or widowed |
| Emotional support | MIHA | Had someone she could talk to who provided emotional support |
| Practical support | MIHA | Had someone who could help her with practical needs, such as transportation or household tasks |
| Health status and health conditions | ||
| Prepregnancy health status | MIHA | Excellent, good, or fair or poor |
| Prepregnancy BMI | MIHA | Obese, overweight, normal, or underweight according to 2009 Institute of Medicine BMI criteria70 |
| Gestational weight gain | MIHA | Inadequate, adequate, or excessive, based on 2009 Institute of Medicine criteria adjusted for prepregnancy BMI and gestational age at birth70 |
| Gestational diabetes | MIHA | A provider told the respondent during this pregnancy that she had diabetes. |
| Gestational hypertension | MIHA | A provider told the respondent during this pregnancy that she had high blood pressure. |
Notes. BMI = body mass index (defined as weight in kilograms divided by the square of height in meters); GED = general equivalency diploma; MIHA = California Maternal and Infant Health Assessment survey; USDA = US Department of Agriculture. All variables from the MIHA survey were self-reported; unless noted otherwise, they refer to the respondent and the index pregnancy.
a
≤ 100% of the federal poverty level (FPL; poor), 101%–200% of the FPL, 201%–400% of the FPL, or > 400% of the FPL.
b
Higher status (professional, executive, or managerial), lower status (all other job titles), student, or unemployed or not working for pay.
c
Categorized as < 25% or ≥ 25% (cutpoint selected because preterm birth rates rose at 25% tract poverty). “Neighborhood” and “census tract” are used interchangeably in this article, despite the fact that census tracts and recognized neighborhoods do not always correspond.