Table 1.
Characteristics of the study population by growth status
| Maternal and infant characteristics | AGA n (%) |
SGAa n (%) |
P * |
|---|---|---|---|
| 319 | 74 | ||
| Birth weight, g (mean±S.D.) | 3292±360 | 2483±259 | <0.01 |
| Standardized birth weight | −0.05±0.63 | −1.76±0.42 | <0.01 |
| Gestational age, weeks (mean±S.D.) | 39.48±1.26 | 39.27±1.26 | 0.19 |
| Infant gender (male) | 164 (51.4) | 36 (48.6) | 0.77 |
| Race | |||
| Black | 235 (73.7) | 57 (77.0) | 0.80 |
| White | 30 (9.4) | 4 (5.4) | |
| Hispanic | 49 (15.4) | 12 (16.2) | |
| Other | 5 (1.6) | 1 (1.4) | |
| Maternal age, year (mean±S.D.) | 28.78±6.64 | 27.30±6.70 | 0.09 |
| Highest level of education | |||
| Middle school or below | 106 (33.2) | 18 (25.0) | <0.01 |
| High school | 94 (29.5) | 36 (50.0) | |
| Above high school | 119 (37.3) | 18 (25.0) | |
| Parity (1+) | 175 (54.9) | 37 (50.0) | 0.53 |
| Smoking before and during pregnancyb | 43 (13.5) | 22 (29.7) | <0.01 |
| Illicit drug use during pregnancy | 26 (8.2) | 14 (18.9) | 0.01 |
| Alcohol use during pregnancy | 7 (2.2) | 1 (1.4) | 1.00 |
| Pre-pregnancy BMI, kg/m2 | |||
| <18.5 | 10 (3.1) | 6 (8.1) | 0.10 |
| ≥18.5 to <25 | 144 (45.1) | 35 (47.3) | |
| ≥25 to <30 | 112 (35.1) | 18 (24.3) | |
| ≥30 | 53 (16.6) | 15 (20.3) | |
| Mode of delivery (vaginal) | 229 (72.7) | 59 (79.7) | 0.27 |
| Hypertensive disordersc | 22 (7.0) | 8 (10.8) | 0.39 |
| Chorioamnionitis, histologicald | 24 (7.5) | 5 (6.8) | 1.00 |
| Chorioamnionitis, clinicale | 6 (2.0) | 2 (2.8) | 0.65 |
| Diabetes | |||
| Gestational diabetes | 15 (4.7) | 1 (1.4) | 0.20 |
| Pre-existing diabetes | 1 (0.3) | 1 (1.4) | |
| Placental abruption | 1 (0.3) | 0 (0.0) | 1.00 |
| Placental previa | 4 (1.3) | 0 (0.0) | 1.00 |
AGA, appropriate for gestational age; SGA, small for gestational age.
a
SGA is defined as <10th percentile, using standardized birth weight.
b
Includes smoking in the 3 months before and during first, second and third trimesters of pregnancy.
c
Includes chronic hypertension, HELLP syndrome, pre-eclampsia or eclampsia.
d
Includes either maternal or fetal inflammatory response by placental pathology.
e
Includes chorioamnionitis as defined by Gibbs et al.31
*
P-value is based upon t-test for continuous variables and χ2 test for categorical variables, and Fisher’s exact test is used for categorical variables, if their table cells have any expected value <5.