Table 1 Baseline characteristics of mothers and infants by hemoglobin (Hb) levels in the second trimester in this study
Total | Hb levels (g/L) | P value | ||||
|---|---|---|---|---|---|---|
< 110 | 110–119 | 120–129 | > 130 | |||
No. of maternal cases | 1911 | 405 | 779 | 583 | 144 | |
Maternal age (years) | 31.0 (29.0, 34.0) | 31.0 (28.5, 35.0) | 31.0 (29.0, 34.0) | 31.0 (29.0, 34.0) | 31.0 (29.0, 35.0) | 0.874 |
Age categories | 0.278 | |||||
< 35 | 1445 (75.6) | 297 (73.3) | 592 (76.0) | 451 (77.4) | 105 (72.9) | |
≥ 35 | 466 (24.4) | 108 (26.7) | 187 (24.0) | 132 (22.6) | 39 (27.1) | |
BMI (kg/m2) | 20.0 (18.4, 21.5) | 20.5 (18.9, 21.9) | 20.7 (19.1, 22.6) | 21.7 (19.7, 23.6) | < 0.001 | |
Education | 0.493 | |||||
Primary | 78 (4.1) | 20 (4.9) | 27 (3.5) | 24 (4.1) | 7 (4.9) | |
Secondary | 285 (14.9) | 68 (16.8) | 122 (15.7) | 78 (13.4) | 17 (11.8) | |
College or above | 1548 (81.0) | 317 (78.3) | 630 (80.9) | 481 (82.5) | 120 (83.3) | |
Conception method | 0.015 | |||||
Natural | 1869 (97.8) | 383 (94.6) | 768 (98.6) | 576 (98.8) | 142 (98.6) | |
Artificial | 26 (1.4) | 12 (3.0) | 7 (0.9) | 5 (0.9) | 2 (1.2) | |
Parity | 0.113 | |||||
Nulliparity | 815 (42.6) | 180 (44.4) | 314 (40.3) | 257 (44.1) | 64 (44.4) | |
Multipara | 1096 (57.4) | 225 (55.5) | 465 (59.7) | 326 (55.9) | 80 (55.6) | |
History of miscarriage | 819 (42.9) | 173 (42.7) | 340 (43.6) | 242 (41.5) | 80 (55.6) | 0.854 |
GDM | 372 (19.5) | 59 (14.6) | 154 (19.8) | 126 (21.6) | 33 (22.9) | 0.029 |
Hemoglobin (g/L) | ||||||
2nd trimester | 117.0 (111.0, 123.0) | 106.0 (102.0, 108.0) | 115.0 (112.5, 117.3) | 123.5 (121.5, 126.0) | 133.0 (131.0, 135.0) | < 0.001 |
3rd trimester | 118 (111.3, 124.3) | 110.3 (105.3, 116.0) | 117.5 (111.7, 122.5) | 122.5 (116.3, 127.3) | 128.2 (119.0, 134.5) | < 0.001 |
Adverse maternal and fetal outcomes | ||||||
PTB | 108 (5.7) | 23 (5.7) | 44 (5.6) | 31 (5.3) | 10 (6.9) | 0.902 |
LBW | 66 (3.5) | 15 (3.7) | 21 (2.7) | 21 (3.6) | 9 (6.3) | 0.184 |
SGA | 86 (4.5) | 24 (5.9) | 31 (4.0) | 24 (4.1) | 7 (4.9) | 0.449 |