Table 1 Demographic data of study population (n = 255)
Variables | n (%) unless stated |
|---|---|
Infant’s age (days)a | 106.0 (10.6) |
Girl | 118 (46.3) |
First-born infant | 233 (91.4) |
Vaginal delivery | 170 (92.5) |
Maternal age (years)a | 31.8 (3.1) |
Paternal age (years)a | 33.8 (3.3) |
Maternal level of education | |
 High school | 19 (7.5) |
 College | 194 (76.1) |
 Graduate school | 42 (16.5) |
Paternal level of educational | |
 High school | 14 (5.5) |
 College | 206 (80.8) |
 Graduate school | 35 (13.7) |
Monthly family income (US dollars) | |
 Less than 2000 | 24 (9.4) |
 2000-4000 | 176 (69.0) |
 More than 4000 | 55 (21.6) |