Table 2 Meta-analysis of association between high maternal Hb and infant outcomes

Timing: high maternal Hb (≥ 130 g/L) by timing

Preconception

1.04^a

(0.96–1.12)

--

1.06^b

(1.00-1.12)

1.02^a

(0.98–1.07)

0.83^a

(0.52–1.33)

--

--

First trimester

1.53

(0.69–3.39)

1.35^a

(1.16–1.57)

1.03

(0.94–1.13)

1.08

(1.00-1.17)

1.23

(1.03–1.47)

---

1.25^a

(0.63–2.49)

Second trimester

1.40^a

(1.02–1.93)

--

1.10

(0.96–1.26)

1.27

(1.08–1.49)

1.07^a

(0.89–1.29)

1.40^a

(0.86–2.29)

--

Third trimester

0.58^a

(0.51–0.66)

--

0.85

(0.61–1.18)

1.14^b

(1.00-1.31)

2.31^a

(1.30–4.10)

--

--

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

≥ 130 g/L

1.50

(0.94–2.39)

1.35^a

(1.16–1.57)

1.12

(1.00-1.25)

1.17

(1.09–1.25)

1.32

(1.09–1.60)

1.40^a

(0.86–2.29)

1.21^b

(0.94–1.57)

≥ 140 g/L

1.37

(0.44–4.23)

1.34^a

(1.05–1.73)

1.14

(0.91–1.43)

1.16

(0.99–1.35)

2.30

(1.38–3.85)

--

--

≥ 150 g/L

0.78^a

(0.19–3.18)

1.43^a

(0.74–2.75)

1.14

(0.77–1.68)

1.11

(0.86–1.44)

--

--

--

≥ 160 g/L

0.78^a

(0.19–3.18)

--

0.42^a

(0.14–1.29)

0.61^a

(0.22–1.67)

--

--

--

Overall estimate*

≥ 130 g/L

1.50

(0.94–2.39)

1.35

(1.16–1.57)

1.12

(1.00-1.25)

1.17

(1.09–1.25)

1.32

(1.09–1.60)

1.40 ^a

(0.86–2.29)

1.21^b

(0.94–1.57)