Table 1.
Characteristics of mothers, offspring, and placentas
| Characteristic | Full eligible sample* (N=30,206) | Final analytic sample (N=13,273) |
|---|---|---|
| Mother | ||
| Pregnancy age (years), mean (SD) | 23.9 (6.0) | 24.3 (6.1) |
| Race, % | ||
| White | 11,008 (36.4) | 4,854 (36.6) |
| Black | 16,547 (54.8) | 7,650 (57.6) |
| Others | 2,651 (8.8) | 769 (5.8) |
| Marital status, % | ||
| Unmarried | 7,931 (26.3) | 3,266 (24.6) |
| Married | 22,275 (73.7) | 10,007 (75.4) |
| Family SES percentile, mean (SD) | 43.7 (21.0) | 45.6 (21.9) |
| Parity, % | ||
| Primiparity | 8,256 (27.5) | 3,624 (27.3) |
| Multiparity | 21,795 (72.5) | 9,649 (72.7) |
| Chronic hypertension, % | 1,102 (3.7) | 541 (4.1) |
| Preeclampsia-eclampsia, % | 5,396 (17.9) | 2,594 (19.5) |
| Offspring | ||
| Sex, % | ||
| Male | 15,164 (50.3) | 6,739 (50.8) |
| Female | 14,990 (49.7) | 6,534 (49.2) |
| Gestational age (weeks), mean (SD) | 39.7 (1.4) | 39.7 (1.4) |
| Birth weight (g), mean (SD) | 3,202 (474) | 3,217 (472) |
| SBP (mmHg), mean (SD) | ||
| At 4 months of age | 86.1 (16.3) | 85.6 (15.5) |
| At 7 years of age | 101.4 (10.2) | 101.2 (9.7) |
| Placenta, mean (SD) | ||
| Placental weight (g) | 439 (93) | 437 (93) |
| Placental largest diameter (cm) | 18.9 (2.2) | 18.9 (2.2) |
| Placental smallest diameter (cm) | 16.5 (2.0) | 16.5 (1.9) |
| Placental area (cm2) | 248 (51) | 247 (51) |
| Placental thickness (cm) | 2.1 (0.5) | 2.1 (0.5) |
| Placental volume (cm3) | 529 (164) | 529 (164) |
| Placental density (g/cm3) | 0.9 (0.4) | 0.9 (0.4) |
SD, standard deviation; SBP, systolic blood pressure; SES, socio-economic status.
*
See Figure 1 for the sample definition. The sum of categories might be not equal to the total because of missing data.