Table 3 Meta-analysis of association between high maternal Hb and maternal outcomes

Timing: low maternal Hb (< 110) by timing

Preconception

--

--

--

1.00^a

(0.97–1.04)

-

--

--

First trimester

--

--

1.42

(0.69–2.95)

0.92^b

(0.73–1.16)

--

--

--

Second trimester

1.43^a

(1.01–2.03)

1.65^a

(0.68-4.00)

0.50^a

(0.29–0.87)

--

1.19^a

(0.80–1.78)

--

--

Third trimester

1.58

(1.40–1.79)

6.15

(3.70-10.23)

1.36

(1.00-1.84)

0.86^a

(0.74-1.00)

1.18

(0.78–1.79)

--

--

Cutoff: low maternal Hb at any time during pregnancy by cutoff

≤ 70 g/L

3.19^b

(0.89–11.37)

43.46^a

(22.06–85.62)

2.83

(2.08–3.85)

--

--

--

3.77^b

(0.77–18.31)

≤ 80 g/L

3.19^b

(0.89–11.70)

24.75^a

(8.15–75.15)

2.83

(2.08–3.85)

--

--

--

3.77^b

(0.77–18.31)

≤ 90 g/L

3.02

(2.04–4.48)

12.07

(6.70-21.72)

2.30

(1.31–4.03)

--

--

--

4.83^b

(2.17–10.74)

≤ 100 g/L

1.92 (

1.42–2.59)

6.45

(3.62–11.49)

1.85

(1.29–2.64)

--

--

1.49^a

(1.22–1.81)

2.87

(1.08–7.67)

≤ 110 g/L

1.69

(1.45–1.97)

3.68

(2.58–5.26)

1.57

(1.23–2.01)

0.88

(0.77-1.00)

1.15

(0.87–1.52)

1.44

(1.24–1.68)

1.93

(0.99–3.76)

Overall estimate*

< 110 g/L

1.69

(1.45–1.97)

3.68

(2.58–5.26)

1.57

(1.23–2.01)

0.88

(0.77-1.00)

1.15

(0.87–1.52)

1.44

(1.24–1.68)

1.93

(0.99–3.76)