Table 1 The characteristics of pregnant women in cases and controls
Characteristics a | Case (n = 244) | Control (n = 244) | Pb |
|---|---|---|---|
Age (year) | |||
Mean ± SD | 31.9 ± 4.0 | 31.1 ± 3.8 | 0.018 |
20–29 | 76 (31.1) | 85 (34.8) | 0.128 |
30–34 | 101 (41.4) | 111 (45.5) | |
≥ 35 | 67 (27.5) | 48 (19.7) | |
BMI (kg/m2) | |||
Mean (SD) | 22.1 ± 3.2 | 21.2 ± 2.4 | < 0.001 |
Slim (BMI < 18.5) | 29 (11.9) | 29 (11.9) | 0.003 |
Normal (18.5 ≤ BMI < 24) | 154 (63.1) | 183 (75.0) | |
Overweight (BMI ≥ 24) | 61 (25.0) | 32 (13.1) | |
Ethnicity | |||
Han | 223 (91.4) | 226 (92.6) | 0.738 |
Others | 21 (8.6) | 18 (7.4) | |
Education level | |||
Junior college and below | 66 (27.0) | 49 (20.1) | 0.164 |
Undergraduate | 123 (50.4) | 140 (57.4) | |
Postgraduate and above | 55 (22.5) | 55 (22.5) | |
Family income (yuan/month) | |||
< 10,000 | 61 (25.0) | 50 (20.5) | 0.336 |
10,000–19,999 | 96 (39.3) | 93 (38.1) | |
≥ 20,000 | 87 (35.7) | 101 (41.4) | |
Parity | |||
Primiparous (= 1) | 157 (64.3) | 186 (76.2) | 0.006 |
Multiparous (≥ 2) | 87 (35.7) | 58 (23.8) | |
GBS infection | |||
Yes | 9 (3.7) | 15 (6.1) | 0.295 |
No | 235 (96.3) | 229 (93.9) | |
Smoke | |||
No | 244 (100) | 244 (100) | / |
Infant sex | |||
Male | 136 (55.7) | 125 (51.2) | 0.364 |
Female | 108 (44.3) | 119 (48.8) | |
Sampling times (gestational weeks) | |||
First trimester | 8.3 ± 1.6 | 8.3 ± 1.7 | 0.892 |
Third trimester | 33.8 ± 0.9 | 33.8 ± 1.1 | 0.824 |