TABLE 2—
Descriptive Statistics by Maternal Stressful Life Events Prior to Conception (PSLEs) and Infant Birth Weight Status: US Early Childhood Longitudinal Study, Birth Cohort, 2001
| PSLEs |
Infant Birth Weight Statusa |
||||||||
| Variable | Total | None | Any | P | Very Low | Low | Normal | High | P |
| Total weighted no. (%) | 3 774 441 (100) | 3 029 554 (80.3) | 744 887 (19.7) | 44 755 (1.2) | 208 987 (5.5) | 3 160 613 (83.7) | 360 085 (9.5) | ||
| Total unweighted no. | 9350 | 7350 | 1950 | 1000 | 1200 | 6500 | 650 | ||
| Birth weight (g) | .201 | < .001 | |||||||
| Mean (SD) | 3333 (583) | 3337 (566) | 3316 (651) | 1044 (828) | 2190 (398) | 3334 (332) | 4270 (204) | ||
| Median | 3373 | 3373 | 3373 | 1036 | 2266 | 3344 | 4196 | ||
| Stress and obstetric factors | |||||||||
| Stressful life events prior to conception | < .001 | ||||||||
| None, % | 80.3 | … | … | 71.3 | 76.1 | 81.1 | 76.9 | ||
| Any, % | 19.7 | … | … | 28.7 | 23.9 | 18.9 | 23.1 | ||
| Mean (SD) | 0.22 (0.48) | 0.00 (–) | 1.13 (0.38) | < .001 | 0.36 (1.91) | 0.29 (0.86) | 0.21 (0.42) | 0.27 (0.45) | < .001 |
| Stressful life events during pregnancy, % | .001 | < .001 | |||||||
| None | 94.2 | 93.8 | 96.0 | 93.5 | 91.8 | 94.2 | 96.2 | ||
| Any | 5.8 | 6.2 | 4.0 | 6.5 | 8.2 | 5.8 | 3.8 | ||
| Pregnancy complications, % | .026 | < .001 | |||||||
| None | 86.4 | 86.9 | 84.6 | 57.5 | 70.1 | 87.9 | 86.4 | ||
| Any | 13.6 | 13.1 | 15.4 | 42.5 | 29.9 | 12.1 | 13.6 | ||
| Maternal chronic conditions, % | .098 | < .001 | |||||||
| None | 79.4 | 79.9 | 77.6 | 60.0 | 69.5 | 80.5 | 78.5 | ||
| Any | 20.6 | 20.1 | 22.4 | 40.0 | 30.5 | 19.5 | 21.5 | ||
| Prior child born preterm or SGA, % | < .001 | < .001 | |||||||
| No | 99.0 | 99.2 | 98.0 | 95.9 | 96.7 | 99.1 | 99.4 | ||
| Yes | 1.0 | 0.8 | 2.0 | 4.1 | 3.3 | 0.9 | 0.6 | ||
| Prepregnancy BMI, kg/m2, % | .369 | < .001 | |||||||
| < 18.5 | 3.3 | 3.3 | 3.5 | 6.1 | 5.1 | 3.4 | 1.3 | *** | |
| 18.5–24.9 | 49.5 | 50.2 | 46.7 | 42.6 | 53.0 | 50.6 | 38.5 | *** | |
| 25–29.9 | 26.8 | 26.6 | 27.6 | 25.1 | 21.8 | 26.8 | 30.1 | * | |
| ≥ 30 | 17.9 | 17.4 | 19.7 | 23.5 | 16.9 | 16.9 | 26.4 | *** | |
| Unknown | 2.5 | 2.5 | 10.6 | 2.8 | 3.2 | 2.3 | 3.8 | ||
| Initiation of prenatal care, % | .246 | <.001 | |||||||
| In the first trimester | 95.5 | 95.5 | 95.8 | 94.0 | 93.0 | 95.6 | 96.3 | * | |
| In the second or third trimester | 4.2 | 4.3 | 3.7 | 4.2 | 6.2 | 4.1 | 3.7 | ||
| Did not receive prenatal care | 0.3 | 0.3 | 0.5 | 1.8 | 0.9 | 0.3 | 0.0 | ** | |
| No. of children born, % | < .001 | < .001 | |||||||
| Singleton | 98.3 | 98.7 | 96.5 | 81.3 | 86.2 | 99.1 | 100.0 | ||
| Multiple | 1.7 | 1.3 | 3.5 | 18.7 | 13.8 | 0.9 | 0.0 | ||
| Parity,b % | < .001 | < .001 | |||||||
| Nulliparous | 40.7 | 44.7 | 24.5 | *** | 46.0 | 46.0 | 41.1 | 33.5 | *** |
| Primaparous | 32.8 | 32.6 | 33.8 | 25.7 | 27.2 | 32.9 | 36.2 | *** | |
| Multiparous | 26.5 | 22.8 | 41.6 | *** | 28.3 | 26.7 | 26.0 | 30.3 | ** |
| Maternal sociodemographic factors | |||||||||
| Age, y, % | < .001 | < .001 | |||||||
| 15–19 | 7.5 | 9.0 | 1.3 | *** | 8.9 | 10.7 | 7.3 | 6.7 | * |
| 20–24 | 24.2 | 27.4 | 11.4 | *** | 25.0 | 27.6 | 24.9 | 16.1 | *** |
| 25–29 | 26.2 | 27.1 | 22.7 | ** | 22.0 | 20.9 | 26.5 | 27.1 | * |
| 30–34 | 25.0 | 23.7 | 30.1 | *** | 26.8 | 20.6 | 24.8 | 28.8 | ** |
| ≥ 35 | 17.1 | 12.9 | 34.4 | *** | 17.3 | 20.2 | 16.4 | 21.3 | ** |
| Race/ethnicity, % | .001 | < .001 | |||||||
| White (non-Hispanic) | 57.4 | 56.4 | 61.3 | ** | 45.9 | 49.8 | 56.9 | 67.4 | *** |
| Black (non-Hispanic) | 14.1 | 14.2 | 13.6 | 27.5 | 23.5 | 14.0 | 7.5 | *** | |
| Asian/Pacific Islander (non-Hispanic) | 3.5 | 3.6 | 3.0 | * | 2.5 | 3.6 | 3.7 | 1.7 | *** |
| Other (non-Hispanic) | 2.5 | 2.4 | 2.8 | 1.9 | 2.3 | 2.6 | 1.6 | ||
| Hispanic | 22.6 | 23.4 | 19.3 | ** | 22.2 | 20.8 | 22.8 | 21.7 | |
| Marital status at delivery, % | < .001 | < .001 | |||||||
| Married or living with partner | 83.4 | 82.9 | 85.5 | * | 77.1 | 75.9 | 83.4 | 88.9 | *** |
| Separated/divorced/widowed | 3.1 | 2.5 | 5.3 | *** | 3.0 | 3.2 | 3.1 | 2.3 | |
| Never married | 13.5 | 14.6 | 9.2 | *** | 19.9 | 20.9 | 13.5 | 8.8 | *** |
| Health insurance status, % | .008 | < .001 | |||||||
| Private only | 59.1 | 58.2 | 62.9 | *** | 52.0 | 50.4 | 58.8 | 68.0 | *** |
| Any public | 37.4 | 38.4 | 33.5 | ** | 43.6 | 45.9 | 37.8 | 29.0 | *** |
| None | 3.4 | 3.4 | 3.5 | 4.3 | 3.8 | 3.4 | 3.0 | ||
| Socioeconomic status, % | < .001 | < .001 | |||||||
| First quintile (lowest) | 19.7 | 20.6 | 15.8 | *** | 23.9 | 24.8 | 19.7 | 16.2 | *** |
| Second quintile | 20.0 | 20.1 | 19.7 | 24.0 | 24.1 | 20.2 | 15.6 | ** | |
| Third quintile | 20.1 | 19.6 | 21.8 | 20.9 | 20.2 | 19.9 | 21.1 | ||
| Fourth quintile | 20.2 | 19.4 | 23.1 | * | 16.8 | 16.1 | 20.2 | 22.2 | * |
| Fifth quintile (highest) | 20.1 | 20.2 | 19.7 | 14.3 | 14.7 | 20.0 | 24.8 | *** | |
| Region of residence, % | .208 | .124 | |||||||
| Northeast | 17.1 | 17.3 | 16.2 | 17.7 | 15.3 | 16.8 | 20.1 | ||
| Midwest | 22.3 | 22.4 | 21.7 | 21.5 | 22.0 | 22.2 | 23.4 | ||
| South | 36.9 | 36.2 | 39.6 | 41.4 | 40.0 | 36.9 | 34.8 | ||
| West | 23.8 | 24.1 | 22.5 | 19.4 | 22.7 | 24.1 | 21.7 | ||
Note. BMI = body mass index; SGA = small for gestational age. Data are weighted percentages or means with standard deviations (SDs). National Center for Education Statistics rounding rules applied to unweighted numbers; unweighted subgroup numbers may not add to the total because of rounding error.
a
Birth weight defined as very low (< 1500 g), low (1500–2499 g), normal (2500–3999 g), or high (≥ 4000 g).
b
Parity of the mother not including her most recent live birth.
*
P < .05;
**
P < .01;
***
P < .001.