Table 1 Baseline characteristics of study population by different areas in Shaanxi province a
Baseline characteristics | Northern Shaanxi n (%) | Central Shaanxi n (%) | Southern Shaanxi n (%) |
|---|---|---|---|
Number of ultrasound examinationb | 2.54 (0.8) | 2.63 (0.7) | 2.58 (0.9) |
Infant Genderb | |||
Male | 4222 (56.4) | 8303 (53.5) | 3189 (54.0) |
Female | 3263 (43.6) | 7295 (46.5) | 2722 (46.0) |
Fetal number | |||
Singleton | 7396 (98.7) | 15522 (98.8) | 5662 (98.9) |
Twin and multi-fetal | 100 (1.3) | 184 (1.2) | 65 (1.1) |
Mother's educationb | |||
College and above | 1044 (13.9) | 3860 (24.6) | 398 (6.7) |
Senior high school | 1156 (15.4) | 3616 (23.0) | 1045 (17.7) |
Junior high school | 3649 (48.7) | 7242 (46.2) | 3541 (60.0) |
Primary school | 1307 (17.4) | 839 (5.3) | 821 (13.9) |
No education | 336 (4.5) | 133 (0.8) | 92 (1.6) |
Mother's age, yearb | |||
< 25 | 2209 (29.8) | 3227 (20.9) | 1792 (30.8) |
25–29 | 3313 (44.6) | 6866 (44.5) | 2148 (36.9) |
≥ 30 | 1899 (25.6) | 5348 (34.6) | 1874 (32.2) |
Parityb | |||
1 | 3770 (50.6) | 9514 (60.8) | 3423 (58.4) |
2 | 3291 (44.2) | 5673 (36.2) | 2292 (39.1) |
≥ 3 | 393 (5.3) | 463 (3.0) | 150 (2.6) |
Wealth indexb | |||
Poor | 2740 (36.5) | 5199 (33.1) | 1706 (28.8) |
Medium | 2322 (31.0) | 5461 (34.8) | 1890 (31.9) |
Rich | 2435 (32.5) | 5048 (32.1) | 2331 (39.3) |
Family history of CHDb | |||
No | 7403 (99.2) | 15559 (99.4) | 5883 (99.7) |
Yes | 59 (0.8) | 92 (0.6) | 19 (0.3) |
Residence during the pregnancyb | |||
Permanent | 6913 (93.2) | 13640 (87.2) | 5120 (86.7) |
Floating | 502 (6.8) | 1996 (12.8) | 785 (13.3) |
Household registrationb | |||
Urban | 1632 (21.8) | 3957 (25.2) | 423 (7.1) |
Rural | 5865 (78.2) | 11751 (74.8) | 5504 (92.9) |
Total | 7497 (25.7) | 15708 (53.9) | 5927 (20.3) |