Maternal characteristics according to pregestational glucose level (N=60 360)
| Characteristics | Hypoglycaemia (<3.9 mmol/L) | Normoglycaemia (3.9–6.0 mmol/L) | Hyperglycaemia (≥6.1 mmol/L) | P value | |
| IFG (6.1–6.9 mmol/L) | Diabetic (≥7.0 mmol/L) | ||||
| No. of pregnancies (%) | 3053 (5.06) | 53 904 (89.30) | 2772 (4.59) | 631 (1.05) | |
| Age, years | <0.001 | ||||
| 20–24 | 1630 (53.39) | 24 630 (45.69) | 1367 (49.31) | 296 (46.91) | |
| 25–29 | 1083 (35.47) | 21 686 (40.23) | 937 (33.81) | 209 (33.12) | |
| 30–34 | 248 (8.13) | 5402 (10.02) | 278 (10.03) | 65 (10.30) | |
| 35–49 | 92 (3.01) | 2186 (4.06) | 190 (6.85) | 61 (9.67) | |
| BMI, kg/m2 | <0.001 | ||||
| <18.5 | 544 (17.82) | 8142 (15.10) | 388 (14.00) | 70 (11.09) | |
| 18.5–23.9 | 2213 (72.49) | 39 360 (73.02) | 2006 (72.37) | 443 (70.21) | |
| 24–27.9 | 251 (8.22) | 5502 (10.21) | 300 (10.82) | 92 (14.58) | |
| ≥28 | 45 (1.47) | 900 (1.67) | 78 (2.81) | 26 (4.12) | |
| Ethnicity | <0.001 | ||||
| Han | 2821 (92.4) | 51 522 (95.58) | 2699 (97.37) | 616 (97.62) | |
| Others | 232 (7.6) | 2382 (4.42) | 73 (2.63) | 15 (2.38) | |
| Education | <0.001 | ||||
| Primary or below | 113 (3.70) | 2237 (4.15) | 209 (7.54) | 57 (9.03) | |
| Middle school | 1391 (45.56) | 23 524 (43.64) | 1331 (48.02) | 321 (50.87) | |
| High school | 846 (27.71) | 13 450 (24.95) | 641 (23.12) | 145 (22.98) | |
| College or above | 703 (23.03) | 14 693 (27.26) | 591 (21.32) | 108 (17.12) | |
| Place of residence | <0.001 | ||||
| Non-agricultural | 714 (23.39) | 14 495 (26.89) | 597 (21.54) | 121 (19.18) | |
| Agricultural | 2339 (76.61) | 39 409 (73.11) | 2175 (78.46) | 510 (80.82) | |
| Occupation | <0.001 | ||||
| Peasant | 1414 (46.32) | 23 590 (43.76) | 1429 (51.55) | 350 (55.47) | |
| Labour worker | 317 (10.38) | 5529 (10.26) | 290 (10.46) | 67 (10.62) | |
| Merchant | 481 (15.75) | 5836 (10.83) | 254 (9.16) | 77 (12.20) | |
| Service staff | 111 (3.64) | 1952 (3.62) | 99 (3.57) | 17 (2.69) | |
| Housewife | 155 (5.08) | 3300 (6.12) | 95 (3.43) | 28 (4.44) | |
| Civil servant | 348 (11.40) | 8598 (15.95) | 301 (10.86) | 50 (7.92) | |
| Others | 227 (7.43) | 5099 (9.46) | 304 (10.97) | 42 (6.66) | |
| Smoking | 0.562 | ||||
| No | 3038 (99.51) | 53 542 (99.33) | 2756 (99.42) | 628 (99.52) | |
| Yes | 15 (0.49) | 362 (0.67) | 16 (0.58) | 3 (0.48) | |
| Passive smoking | <0.001 | ||||
| No | 2433 (79.69) | 45 247 (83.94) | 2419 (87.27) | 548 (86.85) | |
| Yes | 620 (20.31) | 8657 (16.06) | 353 (12.73) | 83 (13.15) | |
| Alcohol | <0.001 | ||||
| No | 2806 (91.91) | 50 799 (94.24) | 2671 (96.36) | 602 (95.40) | |
| Yes | 247 (8.09) | 3105 (5.76) | 101 (3.64) | 29 (4.60) | |
| Gravidity | <0.001 | ||||
| 0 | 1701 (55.72) | 25 330 (46.99) | 1353 (48.81) | 280 (44.37) | |
| ≥1 | 1352 (44.28) | 28 574 (53.01) | 1419 (51.19) | 351 (55.63) | |
| Parity | <0.001 | ||||
| 0 | 2209 (72.36) | 37 820 (70.16) | 1998 (72.08) | 409 (64.82) | |
| ≥1 | 844 (27.64) | 16 084 (29.84) | 774 (27.92) | 222 (35.18) | |
| History of preterm birth | 0.938 | ||||
| No | 3047 (99.80) | 53 777 (99.76) | 2765 (99.75) | 629 (99.68) | |
| Yes | 6 (0.20) | 127 (0.24) | 7 (0.25) | 2 (0.32) | |
| History of spontaneous abortion | 0.013 | ||||
| No | 2942 (96.36) | 51 339 (95.24) | 2643 (95.35) | 610 (96.67) | |
| Yes | 111 (3.64) | 2565 (4.76) | 129 (4.65) | 21 (3.33) | |
| History of induced abortion | <0.001 | ||||
| No | 2190 (71.73) | 34 079 (63.22) | 1808 (65.22) | 421 (66.72) | |
| Yes | 863 (28.27) | 19 825 (36.78) | 964 (34.78) | 210 (33.28) | |
| Hypertension | <0.001 | ||||
| No | 3016 (98.79) | 53 129 (98.56) | 2687 (96.93) | 614 (97.31) | |
| Yes | 37 (1.21) | 775 (1.44) | 85 (3.07) | 17 (2.69) | |
Data were presented as N (%) with p value from χ2 test.
BMI is calculated as the weight in kilograms divided by height in metres squared.
BMI, body mass index; IFG, impaired fasting glycaemia.