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Table 3 Frequencies and prevalence of anemia and IDA

From: Prevalence of anemia and iron deficiency anemia in Chinese pregnant women (IRON WOMEN): a national cross-sectional survey

Outcomes Sample Total (n, %) First trimester
(n,%)
Second trimester
(n,%)
Third trimester
(n,%)
P value1
Anemia All pregnancies 2460 (19.84) 50 (4.91) 577 (16.55) 1833 (23.21) < 0.001
  Singletons 2379 (19.63) 49 (4.92) 547 (16.23) 1783 (23.00) < 0.001
  Multiple gestations 81 (28.72) 1 (4.55) 30 (26.09) 50 (34.48) 0.011
  Maternal age < 35 2055 (19.40) 42 (4.70) 477 (16.04) 1536 (22.83) < 0.001
  Maternal age ≥ 35 405 (22.40) 8 (6.40) 100 (19.49) 297 (25.38) < 0.001
  Nullipara 1520 (18.39) 31 (4.36) 372 (16.25) 1117 (21.22) < 0.001
  Multipara 940 (22.73) 19 (6.23) 205 (17.13) 716 (27.19) < 0.001
IDA All pregnancies 1720 (13.87) 20 (1.96) 293 (8.41) 1407 (17.82) < 0.001
  Singletons 1662 (13.72) 19 (1.91) 276 (8.19) 1367 (17.63) < 0.001
  Multiple gestations 58 (20.57) 1 (4.55) 17 (14.78) 40 (27.59) 0.006
  Maternal age < 35 1449 (13.68) 17 (1.90) 247 (8.31) 1185 (17.62) < 0.001
  Maternal age ≥ 35 271 (14.99) 3 (2.40) 46 (8.97) 222 (18.97) < 0.001
  Nullipara 1031 (12.47) 10 (1.40) 174 (7.40) 847 (16.09) < 0.001
  Multipara 689 (16.66) 10 (3.28) 119 (9.94) 560 (21.27) < 0.001
Previously clinician-diagnosed IDA All pregnancies 3796 (30.61) 53 (5.21) 594 (17.03) 3149 (39.87) < 0.001
Singletons 3699 (30.52) 52 (5.22) 564 (16.73) 3083 (39.77) < 0.001
Multiple gestations 97 (34.52) 1 (4.55) 30 (26.09) 66 (45.52) < 0.001
  Maternal age < 35 3226 (30.45) 48 (5.38) 510 (17.15) 2668 (39.66) < 0.001
  Maternal age ≥ 35 570 (31.53) 5 (4.00) 84 (16.37) 481 (41.11) < 0.001
  Nullipara 2415 (29.21) 37 (5.19) 360 (15.72) 2081 (38.33) < 0.001
  Multipara 1381 (33.40) 16 (5.25) 234 (19.55) 1131 (42.95) < 0.001
  1. 1From Pearson’s chi-square test
  2. IDA iron deficiency anemia