Variables | (-/-) No. (%) | (+/-) No. (%) | (-/+) No. (%) | (+/+) No. (%) | F/χ2 | P |
---|---|---|---|---|---|---|
All participants | 191 | 65 | 95 | 81 | Â | Â |
Sociodemographic characteristics | Â | Â | Â | Â | Â | Â |
 Age, years (mean ± SD) | 31.55 ± 3.57 | 31.43 ± 3.56 | 31.60 ± 3.75 | 31.10 ± 3.23 | 0.51 | 0.47 |
  20–34 | 154 (80.63) | 56 (86.15) | 74 (77.89) | 64 (79.01) | 1.85 | 0.60 |
  35–49 | 37 (19.37) | 9 (13.85) | 21 (22.11) | 17 (20.99) |  |  |
  Missing | 0 | 0 | 0 | 0 |  |  |
 Education level |  |  |  |  |  |  |
  High school or below | 28 (14.66) | 14 (21.54) | 12 (12.64) | 12 (14.81) | - | 0.24a |
  Bachelor degree | 142 (74.35) | 47 (72.31) | 70 (73.68) | 65 (80.25) |  |  |
  Master degree or above | 21 (10.99) | 4 (6.15) | 13 (13.68) | 4 (4.94) |  |  |
  Missing | 0 | 0 | 0 | 0 |  |  |
Health status/lifestyles | Â | Â | Â | Â | Â | Â |
 BMI, kg/m2 (mean ± SD) | 21.25 ± 3.51 | 21.54 ± 2.89 | 21.17 ± 2.68 | 20.94 ± 2.81 | 0.51 | 0.48 |
  Underweight (< 18.50) | 24 (12.57) | 11 (16.92) | 14 (14.74) | 12 (14.81) | 5.35 | 0.50 |
  Normal (18.50–23.90) | 144 (75.39) | 40 (61.54) | 65 (68.42) | 57 (70.37) |  |  |
  Overweight and obesity (≥ 24.00) | 23 (12.04) | 14 (21.54) | 16 (16.84) | 12 (14.82) |  |  |
  Missing | 0 | 0 | 0 | 0 |  |  |
 Hypertension |  |  |  |  |  |  |
  Yes | 1 (0.52) | 1 (1.54) | 2 (2.11) | 3 (3.70) | - | 0.19a |
  No | 190 (99.48) | 64 (98.46) | 93 (97.89) | 78 (96.30) |  |  |
  Missing | 0 | 0 | 0 | 0 |  |  |
 Tobacco exposure |  |  |  |  |  |  |
  Yes | 2 (1.06) | 0 (0.00) | 8 (8.51) | 0 (0.00) | - | < 0.01a |
  No | 187 (98.94) | 63 (100.00) | 86 (91.49) | 81 (100.00) |  |  |
  Missing | 2 | 2 | 1 | 0 |  |  |
 Alcohol intake |  |  |  |  |  |  |
  Yes | 18 (9.42) | 8 (12.31) | 21 (22.11) | 5 (6.17) | 12.96 | < 0.01 |
  No | 173 (90.58) | 57 (87.69) | 74 (77.89) | 76 (93.83) |  |  |
  Missing | 0 | 0 | 0 | 0 |  |  |
Menstrual/reproduction history | Â | Â | Â | Â | Â | Â |
 Regular menstruation |  |  |  |  |  |  |
  Yes | 177 (92.67) | 59 (90.77) | 83 (87.37) | 75 (92.59) | 2.46 | 0.48 |
  No | 14 (7.33) | 6 (9.23) | 12 (12.63) | 6 (7.41) |  |  |
  Missing | 0 | 0 | 0 | 0 |  |  |
 Number of gestation |  |  |  |  |  |  |
  1 | 116 (60.73) | 38 (58.46) | 64 (67.37) | 58 (71.60) | 4.24 | 0.24 |
  ≥ 2 | 75 (39.27) | 27 (41.54) | 31 (32.63) | 23 (28.40) |  |  |
  Missing | 0 | 0 | 0 | 0 |  |  |
 Number of parturition |  |  |  |  |  |  |
  0 | 72 (37.70) | 22 (33.85) | 36 (37.89) | 38 (46.91) | 3.04 | 0.38 |
  ≥ 1 | 119 (62.30) | 43 (66.15) | 59 (62.11) | 43 (53.09) |  |  |
  Missing | 0 | 0 | 0 | 0 |  |  |