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Table 1 Characteristics of participants by serum ferritin concentration at enrolment and postpartum 1

From: The impact of recommending iron supplements to women with depleted iron stores in early pregnancy on use of supplements, and factors associated with changes in iron status from early pregnancy to postpartum in a multi-ethnic population-based cohort

 

 n

Total

SF < 20 μg/L in early pregnancy (depleted iron stores and recommended supplements)

SF ≥ 20 μg/L in early pregnancy (not exposed to recommendations)

 

Total

SF < 15 μg/l postpartum

SF ≥ 15 μg/l postpartum

Total

SF < 15 μg/L postpartum

SF ≥ 15 μg/L postpartum

  

Steady low

Improvement

 

Deterioration

Steady high

n = 573

n = 252 (44)

n = 111

n = 141

n = 321 (56)

n = 114

n = 207

Mean baseline SF (95% CI)

 

33 (30, 35)

11 (11, 12)

11 (10, 12)

12 (11, 12)

50 (46, 54)

45 (40, 50)

53 (47, 58)

Median baseline SF (IQR)

 

23 (12, 41)

11 (7,15)

11 (7, 15)

12 (8, 15)

38 (27, 60)

34 (26, 55)

40 (27, 62)

Gestational week at enrolment

573

15.1 ± 3.4

16.1 ± 3.9

15.7 ± 3.8

16.5 ± 4.0

14.2 ± 2.6

14.2 ± 2.8

14.3 ± 2.6

Postpartum week

565

13.9 ± 2.4

14.0 ± 2.5

14.0 ± 2.7

14.0 ± 2.4

13.9 ± 2.4

13.6 ± 2.4

14.0 ± 2.4

Parous women (≥ 1 previous births)

573

313 (55)

163 (65)

69 (63)

94 (67)

150 (47)

36 (32)

114 (55)

Age at inclusion, years

573

29.7 ± 4.8

29.4 ± 4.9

29.1 ± 5.3

29.6 ± 4.6

30.0 ± 4.8

29.3 ± 4.9

30.3 ± 4.6

Pre-pregnant Body Mass Index, kg/m2

563

24.6 ± 4.8

23.9 ± 4.5

23.9 ± 4.3

23.8 ± 4.7

25.3 ± 4.9

25.4 ± 5.6

25.2 ± 4.5

Western European ethnicity

217

217 (38)

48 (22)

17 (15)

31 (22)

170 (78)

61 (54)

109 (53)

South Asian ethnicity

157

157 (27)

102 (65)

46 (42)

56 (40)

55 (35)

23 (20)

32 (15)

Middle Eastern ethnicity

94

94 (16)

51 (54)

11 (10)

12 (9)

43 (46)

7 (6)

7 (3)

Sub-Saharan African ethnicity

37

37 (7)

23 (62)

5 (5)

5 (4)

14 (38)

7 (6)

16 (8)

East Asian Ethnicity

33

33 (6)

10 (30)

5 (5)

5 (4)

23 (70)

7 (6)

16 (8)

Eastern European ethnicity

34

34 (6)

18 (53)

7 (6)

11 (8)

16 (47)

4 (4)

12 (33)

Socioeconomic position 2

569

0.02 (1.0)

-0.2 (1.0)

-0.4 (1.0)

-0.1 (1.0)

0.2 (1.0)

0.2 (0.9)

0.3 (1.0)

Unhealthy dietary pattern 3

555

391 (70)

202 (82)

95 (86)

107 (76)

189 (61)

80 (70)

109 (53)

Chronic illness / medication associated with normochromic anaemia 4

564

14 (2.5)

4 (1.6)

3 (3)

1 (1)

10 (3.2)

4 (4)

6 (3)

Chronic illness / medication associated with hypochromic anaemia 5

564

55 (10)

24 (10)

10 (90)

14 (10)

31 (10)

8 (7)

23 (11)

Self-reported use of iron supplement in early pregnancy

564

101 (18)

61 (25)

24 (22)

37 (26)

40 (13)

16 (14)

24 (12)

Self-reported use of iron supplement in gestational week 28

538

232 (43)

156 (65)

60 (55)

96 (68)

76 (26)

17 (15)

59 (29)

Self-reported use of iron supplement 14 weeks postpartum

554

124 (22)

69 (28)

25 (23)

44 (31)

55 (18)

20 (18)

35 (17)

Normal vaginal delivery

414

414 (72)

188 (75)

78 (71)

110 (78)

226 (70)

76 (67)

150 (73)

Instrumental vaginal delivery

58

58 (10)

29 (12)

16 (15)

13 (9)

29 (9)

11 (10)

18 (9)

Elective caesarean section

68

68 (12)

25 (10

12 (11)

13 (9)

43 (13)

18 (16)

25 (12)

Emergency caesarean section

29

29 (5)

8 (3)

5 (4)

4 (3)

21 (7)

7 (6)

14 (7)

Birth complications 7

573

97 (17)

35 (14)

15 (14)

20 (14)

62 (19)

30 (26)

32 (15)

Postpartum haemorrhage (≥ 500 mL)

573

33 (5.7)

12 (4.8)

8 (7)

4 (3)

21 (6.5)

13 (11)

8 (4)

  1. Enrolment mean gestational week 15; GW Gestational week, Hb Haemoglobin, Postpartum mean 14 weeks after delivery, SF Serum ferritin
  2. 1 The STORK-G multi ethnic pregnancy cohort from Oslo, Norway, 2008-2010. Values are n (%) or mean ± standard deviation. Group designation: Steady low, SF < 20 μg/L at enrolment and < 15 μg/l postpartum; Improvement, SF < 20 μg/L at enrolment and SF ≥ 15 μg/l postpartum; Deterioration, SF ≥ 20 μg/L at enrolment and SF < 15 μg/l postpartum, and Steady high, SF ≥ 20 μg/L at enrolment and SF ≥ 15 μg/l postpartum
  3. 2 Maternal present socioeconomic position (SEP) was a score derived from a principal component analysis (PCA) of 11 different demographic variables. The variables contributing most to the score, were individual level data about education, occupational class and employment status, and household variables as own or renting tenure and rooms per person in the household. The score was normally distributed, had mean = 0 and SD = 1 (mean and range), with a higher score reflecting higher SEP
  4. 3 Self-reported dietary pattern in gestational week 28 extracted from a food frequency questionnaire
  5. 4 Self-reported chronic illness or medication associated with normochromic anaemia (i.e. kidney or rheumatic disease, use of carbamazepine or infliximab)
  6. 5 Self-reported chronic illness or medication associated with ID and hypochromic anaemia (i.e. gastrointestinal disease or Copper intrauterine device use before conception)
  7. 6 Forceps or vacuum assisted vaginal delivery
  8. 7 A composite variable created by combining following 4 birth complication; episiotomy, third—and fourth degree perineal tear, obstructed labour, and manual removal of placenta