Table 1 General characteristics of PIH cases and controls
Characteristics | Controls (n = 184) | Cases (n = 92) | P valuea |
|---|---|---|---|
Age (years) | 29.2 ± 3.7 | 29.8 ± 4.1 | NA |
Infant sex | NA | ||
Male | 124 (67.4) | 62 (67.4) | |
Female | 60 (32.6) | 30 (32.6) | |
Pre-pregnancy BMI (kg/m2) | 20.3 ± 2.5 | 23.2 ± 3.9 | <0.0001 |
Underweight (<18.5) | 39 (21.2) | 9 (9.8) | <0.0001 |
Normal (18.5–23.9) | 132 (71.7) | 47 (51.1) | |
Overweight or obese (≥24) | 13 (7.1) | 36 (39.1) | |
Education | 0.27 | ||
High school and lower | 32 (17.4) | 23 (25.0) | |
Junior college | 55 (29.9) | 28 (30.4) | |
University and higher | 97 (52.7) | 41 (44.6) | |
Parity | 0.52 | ||
Nulliparous | 163 (88.6) | 79 (85.9) | |
Multiparous | 21 (11.4) | 13 (14.1) | |
Active smoking during pregnancy | 0.47 | ||
Yes | 2 (1.1) | 2 (2.2) | |
No | 182 (98.9) | 89 (96.7) | |
Missing | 0 (0.0) | 1 (1.1) | |
Passive smoking during pregnancy | 0.38 | ||
Yes | 58 (31.5) | 24 (26.1) | |
No | 126 (68.5) | 67 (72.8) | |
Missing | 0 (0.0) | 1 (1.1) | |
Alcohol use during pregnancy | 0.11 | ||
Yes | 5 (2.7) | 0 (0.0) | |
No | 179 (97.3) | 91 (98.9) | |
Missing | 0 (0.0) | 1 (1.1) | |
Calcium supplementation during pregnancy | 0.24 | ||
Yes | 169 (91.8) | 88 (95.6) | |
No | 15 (8.2) | 4 (4.4) | |
Iron supplementation during pregnancy | 0.65 | ||
Yes | 79 (42.9) | 35 (38.0) | |
No | 105 (57.1) | 57 (62.0) | |
Multivitamin supplementation during pregnancy | 0.44 | ||
Yes | 167 (90.8) | 85 (92.4) | |
No | 17 (9.2) | 7 (7.6) | |
Physical activity during pregnancy | 0.22 | ||
No | 17 (9.2) | 9 (9.8) | |
≤4 d/week | 19 (10.3) | 16 (17.4) | |
>4 d/week | 144 (78.3) | 64 (69.5) | |
Missing | 4 (2.2) | 3 (3.3) | |
Gestational age | 38.86 ± 1.10 | 38.24 ± 1.77 | 0.002 |
Preterm delivery | 0.02 | ||
<37 weeks | 6 (3.3) | 9 (9.8) | |
≥37 weeks | 178 (96.7) | 83 (90.2) | |
Low birth weight | <0.0001 | ||
Yes | 2 (1.1) | 12 (13.0) | |
No | 182 (98.9) | 80 (87.0) | |
Small for gestational age | 0.02 | ||
Yes | 12 (6.5) | 14 (15.2) | |
No | 172 (93.5) | 78 (84.8) |
