# Table 2 Characteristics of the participants by parity

Characteristics Total (N = 1209) Nullipara (n = 841) Multipara (n = 368) Statistic P value
Age (years), n (%)     191.721a <.001
20-24y 78 (6.5) 57 (6.8) 21 (5.7)
25-29y 533 (44.1) 462 (54.9) 71 (19.3)
30-34y 456 (37.7) 276 (32.8) 180 (48.9)
35-39y 119 (9.8) 44 (5.2) 75 (20.4)
≥ 40y 23 (1.9) 2 (0.2) 21 (5.7)
Educational level, n (%)     9.067a 0.028
Junior high school or below 162 (13.4) 102 (12.1) 60 (16.3)
Senior high/ technical school 250 (20.7) 169 (20.1) 81 (22.0)
College graduate 597 (49.4) 438 (52.1) 159 (43.2)
Postgraduate 200 (16.5) 132 (15.7) 68 (18.5)
Household monthly income per capita, CNY, n (%)     0.605a 0.895
< 5000 95 (7.9) 69 (8.2) 26 (7.1)
5000-7999 239 (19.8) 168 (20.0) 71 (19.3)
8000-10,000 279 (23.1) 193 (22.9) 86 (23.4)
> 10,000 596 (49.3) 411 (48.9) 185 (50.3)
Gestational weeks, mean (SD) 39.56 (1.02) 39.66 (1.02) 39.34 (1.01) 5.159b 0.762
Prepregnancy weight category, n (%)     7.536a 0.057
Underweight (BMI < 18.5 kg/m2) 226 (18.7) 146 (17.4) 80 (21.7)
Normal weight (BMI 18.5–24.9 kg/m2) 875 (72.4) 613 (72.9) 262 (71.2)
Overweight (BMI 25.0–29.9 kg/m2) 100 (8.3) 78 (9.3) 22 (6.0)
Obese (BMI ≥ 30.0 kg/m2) 8 (0.7) 4 (0.5) 4 (1.1)
GWG, n (%)     6.665a 0.036
Inadequate GWG (1)(4)(7)(10)c 254 (21.0) 175 (20.8) 79 (21.5)
Adequate GWG (2)(5)(8)(11)c 589 (48.7) 393 (46.7) 196 (53.3)
Excessive GWG (3)(6)(9)(12)c 366 (30.3) 273 (32.5) 93 (25.3)
1. CNY Chinese Yuan; BMI Body mass index; GWG Gestational weight gain
2. a Chi-square test; bt test;
3. c Numbers in parentheses indicate number for category of gestational weight gain listed in Table 1