Table 1. Descriptive statistics at delivery.
| Sociodemographic characteristics of mothers and their children at delivery (baseline) | (N = 767) | (N = 632) |
| Mother’s age at delivery, years, mean (SD) [median] | 33.1 (4.4) [33] | 33.3 (4.3) [33] |
| Maternal BMI before pregnancy, mean (SD) [median] | 22.6 (3.8) [21.9] | 22.7 (3.8) [22.1] |
| Weight gain during pregnancy, kg, mean (SD) [median] | 13.4 (4.5) [13.0] | 13.4 (4.5) [13.0] |
| Mother’s occupation, n (%) | ||
| Employed on maternity | 572 (75.8) | 473 (75.9) |
| Employed worker | 67 (8.9) | 56 (9.0) |
| Housewife | 68 (9.0) | 51 (8.2) |
| Other condition | 48 (6.4) | 43 (6.9) |
| Mothers’ marital status, n (%) | ||
| Married/Living together | 683 (89.9) | 565 (90.4) |
| Widow/single/never married/separated/divorcing | 77 (10.1) | 60 (9.6) |
| Mother’s educational level, n (%) | ||
| Elementary and middle school | 139 (18.2) | 105 (16.7) |
| High school | 364 (47.6) | 304 (48.2) |
| University degree | 262 (34.3) | 221 (35.1) |
| Maternal Intelligence Quotient, Raven’s Progressive Matrices, mean (SD) [median] | 118.2 (11.7) [123] | 118.9 (11.2) [125] |
| Home size, n (%) | ||
| <50 mq | 53 (7.0) | 46 (7.4) |
| 50–100 mq | 514 (67.8) | 421 (67.5) |
| >100 mq | 191 (25.2) | 157 (25.2) |
| Number of cigarettes smoked, by mother, during pregnancy, mean (SD) [median] | 170.9 (606.1) [0] | 154.9 (584.3) [0] |
| Alcoholic drinks per week during pregnancy, number of glasses per week, mean (SD) [median] | 1.5 (2.9) [0.3) | 1.5 (2.8) [0.3] |
| Fish consumption of mother during pregnancy, 150-gram servings/week, mean (SD) [median] | 1.5 (1.1) [1.1] | 1.5 (1.1) [1.1) |
| Children’s sex, n (%) | ||
| Male | 385 (50.5) | 314 (50.0) |
| Female | 377 (49.5) | 314 (50.0) |
| Birth weight, g, mean (SD) [median] | 3,392.5 (466.3) [3,380.0] | 3,404.2 (469.8) [3,397.5) |
| Birth length, cm, mean (SD) [median] | 50.0 (2.1) [50.0)] | 50.1 (2.2) [50.0] |
SD, standard deviation.