Table 3.
Characteristics of included pregnant women by prepregnancy body mass index categories
| Characteristics at baseline | Overall (n = 8,356) | Underweight (n = 1,287) | Normal (n = 6,437) | Overweight (n = 632) | P‐value |
|---|---|---|---|---|---|
| Maternal age (years) | |||||
| 19–24 | 383 (4.58) | 113 (8.78) | 255 (3.96) | 15 (2.37) | <0.001 |
| 25–29 | 3,400 (40.69) | 666 (51.75) | 2,554 (39.68) | 180 (28.48) | |
| 30–34 | 3,377 (40.41) | 419 (32.56) | 2,661 (41.34) | 297 (46.99) | |
| 35–46 | 1,196 (14.31) | 89 (6.92) | 967 (15.02) | 140 (22.15) | |
| Education years | |||||
| ≥17 | 1,242 (14.86) | 168 (13.05) | 1,014 (15.75) | 60 (9.49) | <0.001 |
| 13–16 | 6,248 (74.77) | 1,002 (77.86) | 4,786 (74.35) | 460 (72.78) | |
| 10–12 | 593 (7.10) | 89 (6.92) | 436 (6.77) | 68 (10.76) | |
| <10 | 273 (3.27) | 28 (2.18) | 201 (3.12) | 44 (6.96) | |
| Residence | |||||
| Urban | 7,339 (87.83) | 1,143 (88.81) | 5,656 (87.87) | 540 (85.44) | 0.10 |
| Rural | 1,017 (12.17) | 144 (11.19) | 781 (12.13) | 92 (14.56) | |
| Gravidity | |||||
| 1 | 3,675 (43.98) | 669 (51.98) | 2,790 (43.34) | 216 (34.18) | <0.001 |
| >1 | 4,681 (56.02) | 618 (48.02) | 3,647 (56.66) | 416 (65.82) | |
| Parity | |||||
| Primipara | 6,971 (83.43) | 1,153 (89.59) | 5,336 (82.90) | 482 (76.27) | <0.001 |
| Multipara | 1,385 (16.57) | 134 (10.41) | 1,101 (17.10) | 150 (23.73) | |
| GDM history | |||||
| No | 8,327 (99.65) | 1,282 (99.61) | 6,417 (99.69) | 628 (99.37) | 0.29† |
| Yes | 29 (0.35) | 5 (0.39) | 20 (0.31) | 4 (0.63) | |
| In vitro fertilization | |||||
| No | 8,078 (96.67) | 1,273 (98.91) | 6,213 (96.52) | 592 (93.67) | <0.001 |
| Yes | 278 (3.33) | 14 (1.09) | 224 (3.48) | 40 (6.33) | |
| Cardiovascular diseases | |||||
| No | 8,092 (96.84) | 1,249 (97.05) | 6,242 (96.97) | 601 (95.09) | 0.03 |
| Yes | 264 (3.16) | 38 (2.95) | 195 (3.03) | 31 (4.91) | |
| Viral hepatitis | |||||
| No | 7,969 (95.37) | 1,239 (96.27) | 6,129 (95.22) | 601 (95.09) | 0.24 |
| Yes | 387 (4.63) | 48 (3.73) | 308 (4.78) | 31 (4.91) | |
| Endocrine diseases | |||||
| No | 7,488 (89.61) | 1,145 (88.97) | 5,785 (89.87) | 555 (87.82) | 0.20 |
| Yes | 871 (10.42) | 142 (11.03) | 652 (10.13) | 77 (12.18) | |
| Hematological diseases | |||||
| No | 8,062 (96.48) | 1,245 (96.74) | 6,199 (96.30) | 618 (97.78) | 0.13 |
| Yes | 294 (3.52) | 42 (3.26) | 238 (3.70) | 14 (2.22) | |
| Respiratory diseases | |||||
| No | 8,340 (99.81) | 1,286 (99.92) | 6,422 (99.77) | 632 (100) | 0.38† |
| Yes | 16 (0.19) | 1 (0.08) | 15 (0.23) | 0 (0.00) | |
| Urinary diseases | |||||
| No | 8,334 (99.74) | 1,285 (99.84) | 6,417 (99.69) | 632 (100) | 0.40† |
| Yes | 22 (0.26) | 2 (0.16) | 20 (0.31) | 0 (0.00) | |
| Immune diseases | |||||
| No | 8,318 (99.55) | 1,278 (99.30) | 6,413 (99.63) | 627 (99.21) | 0.09† |
| Yes | 38 (0.45) | 9 (0.70) | 24 (0.37) | 5 (0.79) | |
| Neuropsychiatric diseases | |||||
| No | 8,336 (99.76) | 1,285 (99.84) | 6,419 (99.72) | 632 (100) | 0.51† |
| Yes | 20 (0.24) | 2 (0.16) | 18 (0.28) | 0 (0.00) | |
| Reproductive diseases | |||||
| No | 7,722 (92.41) | 1,232 (95.73) | 5,927 (92.08) | 563 (89.08) | <0.001 |
| Yes | 634 (7.59) | 55 (4.27) | 510 (7.92) | 69 (10.92) | |
Data are shown by frequency (percentage). †Fisher’s exact test. BMI, body mass index; GDM, gestational diabetes mellitus. P value in bold indicates statistical significance.