Table 1 Characteristics of included and excluded mother-child pairs
Characteristics | Included (N = 533) n (%) / Mean ± SD | Excluded (N = 692) n (%) / Mean ± SD | P-value of Student’s t-test or Chi-square test |
|---|---|---|---|
Maternal age at enrollment (years) | |||
Mean ± SD | 27.9 ± 3.4 | 27.8 ± 3.4 | 0.7451 |
< 25 | 81 (15.2) | 103 (14.9) | 0.7900 |
25–30 | 299 (56.1) | 404 (58.4) | |
≥ 30 | 153 (28.7) | 185 (26.7) | |
Maternal pre-pregnancy BMI (kg/m2) | |||
Mean ± SD | 20.6 ± 2.4 | 20.4 ± 2.4 | 0.1905 |
< 18.5 | 98 (18.7) | 146 (21.5) | 0.2112 |
18.5–24.9 | 395 (75.4) | 506 (74.4) | |
≥ 25 | 31 (5.9) | 28 (4.1) | |
Maternal education | |||
Blow high school | 41 (7.7) | 78 (11.3) | 0.1064 |
High School | 76 (14.3) | 99 (14.3) | |
College or above | 415 (78.0) | 514 (74.4) | |
Paternal education | |||
Blow high school | 28 (5.25) | 57 (8.28) | 0.9430 |
High School | 76 (14.26) | 119 (17.3) | |
College or above | 429 (80.49) | 512 (74.42) | |
Per capita household income (CNY) | |||
< 4000 | 113 (21.3) | 140 (20.6) | 0.0282 |
4000–8000 | 212 (40.0) | 277 (40.8) | |
> 8000 | 205 (38.7) | 262 (38.6) | |
Parity | |||
Nulliparous | 459 (86.9) | 569 (82.7) | 0.0432 |
Multiparous | 69 (13.1) | 119 (17.3) | |
Maternal alcohol consumption during pregnancy | |||
No | 454 (99.13) | 508 (98.64) | 0.4743 |
Yes | 4 (0.87) | 7 (1.36) | |
Maternal passive smoking before conception | |||
No | 307 (57.8) | 420 (60.9) | 0.2811 |
Yes | 224 (42.2) | 270 (39.1) | |
Maternal prenatal depressive symptoms | |||
No | 434 (81.43) | 551 (79.62) | 0.4309 |
Yes | 99 (18.57) | 141 (20.38) | |
Sex of child | |||
Boy | 297 (55.7) | 370 (53.7) | 0.4816 |
Girl | 236 (44.3) | 319 (46.3) | |
Gestational age (weeks) | |||
Mean ± SD | 39.5 ± 1.3 | 39.51 ± 1.5 | 0.6182 |
< 37 | 19 (3.6) | 26 (3.8) | 0.8640 |
≥ 37 | 513 (96.4) | 666 (96.2) | |