Table 1.
Characteristics of the study population (n = 570).
| Variable | No. (%) | Birth weight (g) | p-Valuea |
|---|---|---|---|
| Categorized variable
| |||
| Child’s sex | < 0.001 | ||
| Male | 288 (50.5) | 3,316 | |
| Female | 282 (49.5) | 3,177 | |
| Season of conception | 0.04 | ||
| Spring | 158 (27.7) | 3,217 | |
| Summer | 167 (29.3) | 3,248 | |
| Fall | 132 (23.2) | 3,332 | |
| Winter | 113 (19.8) | 3,188 | |
| Tobacco smoking during pregnancy | < 0.001 | ||
| 0 | 467 (83.7) | 3,277 | |
| 1–5 cigarettes/day | 61 (10.9) | 3,200 | |
| > 5 cigarettes/day | 30 (5.4) | 3,023 | |
| Passive smoking during pregnancy | 0.03 | ||
| Yes | 241 (43.2) | 3,207 | |
| No | 317 (56.8) | 3,285 | |
| Maternal parity | 0.09 | ||
| 0 | 323 (56.9) | 3,221 | |
| ≥ 1 | 245 (43.1) | 3,283 | |
| Maternal education | 0.11 | ||
| Primary education | 166 (29.3) | 3,197 | |
| Secondary education | 237 (41.8) | 3,258 | |
| University degree | 164 (28.9) | 3,274 | |
| Maternal race/ethnicity | 0.01 | ||
| White/Caucasian | 551 (96.8) | 3,238 | |
| Latin American | 14 (2.5) | 3,595 | |
| Black | 4 (0.7) | 3,136 | |
| Continuous variables | Median | IQR | p-Valueb |
| Maternal age (years) | 31.1 | 5.7 | 0.43 |
| Gestational age (weeks) | 39.9 | 1.9 | < 0.001 |
| Maternal height (cm) | 162 | 8.3 | 0.01 |
| Maternal prepregnancy weight (kg) | 60 | 14 | < 0.001 |
| Paternal height (cm) | 175 | 8 | 0.02 |
| Paternal weight (kg) | 79 | 15 | 0.01 |
a
p-Values for comparing means by t-test or analysis of variance.
b
p-Values of Pearson correlation coefficients between each continuous variable and birth weight.