Background
Methods
Data sources
Study design and population
Prevalence of anaemia
Related risk factors
Anaemia and adverse pregnancy outcomes
Definitions
Statistical analysis
Results
Prevalence of anaemia among pregnant women
Variables | Anaemic | Non-anaemic | Total |
---|---|---|---|
Pregnant women | 10,199 (23.5%) | 33,204 (76.5%) | 43,403 (100.0%) |
Maternal age (years) | 29.50 ± 4.46 | 29.80 ± 4.19 | 29.73 ± 4.25 |
Gravidity | 1.94 ± 1.20 | 1.85 ± 1.13 | 1.87 ± 1.15 |
Parity | 0.78 ± 0.73 | 0.59 ± 0.67 | 0.64 ± 0.69 |
Pre-pregnancy BMI (kg/m2) | 20.57 ± 4.39 | 21.31 ± 4.41 | 21.13 ± 4.42 |
Pre-pregnancy height (cm) | 54.00 ± 8.38 | 56.42 ± 9.18 | 55.85 ± 9.06 |
Pre-pregnancy weight (kg) | 160.48 ± 4.96 | 161.56 ± 4.92 | 161.30 ± 4.95 |
Number | Percent | Hb (g/L) | Testing time (week) | |
---|---|---|---|---|
1st trimester | 26,924 | 61.2 | 129.89 ± 9.90 | 10.65 ± 2.72 |
2nd trimester | 33,879 | 77.0 | 118.99 ± 9.78 | 23.17 ± 3.39 |
3rd trimester | 41,569 | 94.5 | 121.21 ± 12.62 | 37.24 ± 2.71 |
Total | Anaemia | Severity of anaemia | |||||||
---|---|---|---|---|---|---|---|---|---|
Mild | Moderate | Severe | |||||||
N
|
N
| % |
N
| % |
N
| % |
N
| % | |
1st trimester | 26,924 | 732 | 2.7 | 567 | 77.5 | 165 | 22.5 | 0 | – |
2nd trimester | 33,879 | 4996 | 14.7 | 4144 | 82.9 | 848 | 17.0 | 4 | 0.1 |
3rd trimester | 41,569 | 6888 | 16.6 | 5073 | 73.6 | 1800 | 26.1 | 15 | 0.2 |
Factors associated with anaemia
Variables | Anaemic | Non-anaemic | Total |
---|---|---|---|
Haemoglobin (g/L) | 103.31 ± 5.88 | 130.55 ± 8.89 | 129.80 ± 9.88 |
Gestation week (weeks) | 11.32 ± 2.38 | 10.63 ± 2.73 | 10.65 ± 2.72 |
Maternal age (years) | 29.91 ± 4.43 | 30.02 ± 3.93 | 30.01 ± 3.94 |
Gravidity | 1.96 ± 1.21 | 1.77 ± 1.09 | 1.78 ± 1.10 |
Parity | 0.83 ± 0.72 | 0.51 ± 0.63 | 0.52 ± 0.63 |
Pre-pregnancy BMI (kg/m2) | 20.34 ± 3.88 | 21.23 ± 4.13 | 21.20 ± 4.13 |
Pre-pregnancy height (cm) | 160.45 ± 4.67 | 161.77 ± 4.91 | 161.74 ± 4.91 |
Pre-pregnancy weight (kg) | 53.00 ± 7.64 | 56.13 ± 8.76 | 56.05 ± 8.75 |
Variables | Anaemic | Non-anaemic |
χ
2
| P-value |
---|---|---|---|---|
Pregnant women | 719 (23.5%) | 25,536 (76.5%) | ||
Maternal age | ||||
< 20y | 5 (8.2%) | 56 (91.8%) | 15.424 | < 0.001* |
20-35 | 616 (2.6%) | 22,850 (97.4%) | ||
≥ 35 | 98 (3.6%) | 2630 (96.4%) | ||
Educational status | ||||
College and above | 485 (2.3%) | 20,168 (97.7%) | 69.346 | < 0.001* |
Junior or senior | 224 (4.5) | 4748 (95.5%) | ||
Primary or illiteracy | 3 (3.3%) | 88 (96.7%) | ||
Cities | ||||
Beijing | 296 (1.6%) | 17,951 (98.4%) | 477.503 | < 0.001* |
Guangzhou | 164 (10.5%) | 1400 (89.5%) | ||
Chengdu | 259 (4.0%) | 6185 (96.0%) | ||
Family per capita monthly income (CNY) | ||||
< 1000 | 140 (2.2%) | 6170 (97.8%) | 9.256 | 0.010* |
1000-4999 | 262 (2.9%) | 8667 (97.1%) | ||
≥ 5000 | 308 (2.9%) | 10,141 (97.1%) | ||
Residence | ||||
Urban | 487 (2.4%) | 19,671 (97.6%) | 36.801 | < 0.001* |
Rural | 226 (3.9%) | 5580 (96.1%) | ||
Pre-pregnancy BMI (kg/m2) | ||||
< 18.5 | 152 (3.6%) | 4046 (96.4%) | 35.163 | < 0.001* |
18.5-23.99 | 483 (2.8%) | 17,737 (97.2%) | ||
24-27.99 | 62 (1.7%) | 3589 (98.3%) | ||
≥ 28 | 13 (1.3%) | 980 (98.7%) | ||
Parity | ||||
0 | 246 (1.7%) | 14,316 (98.3%) | 148.303 | < 0.001* |
1-3 | 463 (4.0%) | 11,101 (96.0%) | ||
≥ 4 | 8 (11.0%) | 65 (89.0%) |
Variables | COR | 95%CI | P-value | AOR | 95%CI | P-value |
---|---|---|---|---|---|---|
Maternal age | ||||||
< 20y | 3.312 | 1.322-8.297 | 0.011* | 2.489 | 0.958-6.467 | 0.061 |
20-35 | 1 | 1 | ||||
≥ 35 | 1.382 | 1.113-1.717 | 0.003* | 1.386 | 1.103-1.742 | 0.005* |
Educational status | ||||||
College and above | 1 | – | ||||
Junior or senior | 0.705 | 0.222-2.237 | 0.553 | – | ||
Primary or illiteracy | 1.384 | 0.434-4.408 | 0.583 | – | ||
Cities | ||||||
Beijing | 1 | 1 | ||||
Guangzhou | 7.104 | 5.826-8.663 | < 0.001* | 7.293 | 5.455-9.751 | < 0.001* |
Chengdu | 2.540 | 2.144-3.008 | < 0.001* | 2.847 | 2.147-3.777 | < 0.001* |
Family per capita monthly income (RMB, CYN) | ||||||
< 1000 | 0.747 | 0.610-0.915 | 0.005* | 1.671 | 1.291-2.162 | < 0.001* |
1000-4999 | 0.995 | 0.842-1.176 | 0.956 | 1.157 | 0.968-1.382 | 0.109 |
≥ 5000 | 1 | 1 | ||||
Residence | ||||||
Urban | 1 | 1 | ||||
Rural | 1.636 | 1.393-1.921 | < 0.001* | 1.308 | 1.095-1.563 | 0.003* |
Pre-pregnancy BMI (kg/m2) | ||||||
< 18.5 | 1.302 | 1.081-1.567 | 0.005 | 1.237 | 1.021-1.498 | 0.030* |
18.5-23.99 | 1 | 1 | ||||
24-27.99 | 0.599 | 0.458-0.782 | < 0.001* | 0.662 | 0.506-0.867 | 0.003* |
≥ 28 | 0.460 | 0.264-0.800 | 0.006* | 0.506 | 0.283-0.906 | 0.022* |
Parity | ||||||
0 | 1 | 1 | ||||
1-3 | 2.427 | 2.075-2.839 | < 0.001* | 1.071 | 0.842-1.363 | 0.576 |
≥ 4 | 7.162 | 3.400-15.089 | < 0.001* | 2.130 | 0.920-4.932 | 0.078 |
The risk of adverse pregnancy outcomes
Variables | Anaemic | Non-anaemic | Total |
---|---|---|---|
Pregnant women | 6476 (16.4%) | 32,963 (83.6%) | 39,439 (100%) |
Haemoglobin (g/L) | 102.16 ± 6.64 | 125.09 ± 9.64 | 121.32 ± 12.53 |
Gestation week | 22.65 ± 3.61 | 23.25 ± 3.36 | 23.17 ± 3.40 |
Maternal age (years) | 29.21 ± 4.48 | 29.74 ± 4.18 | 29.66 ± 4.23 |
Gravidity | 1.99 ± 1.21 | 1.83 ± 1.13 | 1.86 ± 1.14 |
Parity | 0.86 ± 0.74 | 0.59 ± 0.67 | 0.63 ± 0.69 |
Pre-pregnancy BMI (kg/m2) | 20.48 ± 4.51 | 21.14 ± 4.33 | 21.04 ± 4.36 |
Pre-pregnancy height (cm) | 160.39 ± 4.92 | 161.48 ± 4.92 | 161.30 ± 4.93 |
Pre-pregnancy weight (kg) | 53.96 ± 8.30 | 55.93 ± 8.89 | 55.61 ± 8.83 |
Variables | Anaemic | Non-anaemic | χ2 |
P
|
---|---|---|---|---|
Caesarean section | 2986(46.1%) | 15,031(45.6%) | 0.565 | 0.452 |
GDM | 1031(15.9%) | 6575(19.9%) | 56.368 | < 0.001* |
Hypertensive disorder | 165 (2.5%) | 863 (2.6%) | 0.105 | 0.746 |
PROM | 1319(20.4%) | 7021 (21.3%) | 2.820 | 0.093 |
Foetal distress | 611(9.4%) | 4119(12.5%) | 48.049 | < 0.001* |
Placenta abruption | 28 (0.40) | 147(0.4%) | 0.23 | 0.880 |
Polyhydramnios | 125 (1.95) | 386 (1.2%) | 24.394 | < 0.001* |
Oligohydramnios | 168 (2.6%) | 1202 (3.6%) | 17.876 | < 0.001* |
Preterm labour | 529 (8.2%) | 1600 (4.9%) | 116.45 | < 0.001* |
Low birth weight (< 2500 g) | 319 (4.9%) | 1108(3.4%) | 37.991 | < 0.001* |
Neonatal complications | 687 (10.6%) | 2501 (7.6%) | 66.489 | < 0.001* |
NICU admission | 631 (9.7%) | 2000 (6.1%) | 117.492 | < 0.001* |