Table 2

Associations between maternal genotype at individual iron-related SNPs, maternal genotypic risk scores and haemoglobin concentrations in early and late pregnancy in ALSPAC

SNPs	Risk allele*	Early pregnancy (n=5219)		Late pregnancy (n=5438)
SNPs	Risk allele*	β† (95% CI)	P trend	β† (95% CI)	P trend
rs1799945	C	−0.07 (−0.12 to –0.02)	0.005	−0.09 (−0.14 to –0.04)	2.3×10⁻⁴
rs1800562	G	−0.13 (−0.20 to –0.06)	1.5×10⁻⁴	−0.19 (−0.26 to –0.13)	1.1×10⁻⁸
rs855791	A	−0.11 (−0.15 to –0.08)	1.8×10⁻¹⁰	−0.12 (−0.15 to –0.08)	1.3×10⁻¹¹
rs8177240	T/G‡	0.02 (−0.02 to 0.05)	0.34	−0.02 (−0.06 to 0.01)	0.23
rs7385804	C	0.01 (−0.03 to 0.04)	0.77	0.00 (−0.03 to 0.04)	0.79
rs744653	T	−0.04 (−0.09 to 0.01)	0.10	0.00 (−0.04 to 0.05)	0.88
rs651007	T	−0.04 (−0.08 to 0.00)	0.07	−0.05 (−0.09 to –0.01)	0.02
rs411988	A	−0.02 (−0.06 to 0.01)	0.17	0.00 (−0.03 to 0.03)	0.99
rs9990333	C	0.01 (−0.03 to 0.04)	0.71	0.01 (−0.03 to 0.04)	0.69
rs4921915	A	−0.03 (−0.07 to 0.01)	0.15	−0.02 (−0.06 to 0.02)	0.43
rs6486121	C	0.00 (−0.03 to 0.04)	0.96	0.01 (−0.03 to 0.04)	0.62
rs174577	A	0.00 (−0.03 to 0.04)	0.79	−0.01 (−0.05 to 0.03)	0.57
Iron score		−0.09 (−0.11 to –0.06)	2.3×10⁻¹²	−0.11 (−0.13 to –0.08)	1.8×10⁻¹⁸
Ferritin score		−0.09 (−0.12 to –0.07)	6.1×10⁻¹³	−0.09 (−0.12 to –0.07)	8.2×10⁻¹⁴
Transferrin score		−0.05 (−0.07 to –0.03)	4.8×10⁻⁵	−0.04 (−0.07 to –0.02)	7.6×10⁻⁴
Transferrin saturation score		−0.09 (−0.11 to –0.06)	9.8×10⁻¹³	−0.11 (−0.12 to –0.08)	5.5×10⁻¹⁶

*Associated with lower iron status, lower ferritin status, higher transferrin status or lower transferrin saturation status with p<5.10⁻⁸.
†Per risk allele effect estimates are reported for SNPs, per SD increase effect estimates are reported for scores.
‡T is the risk allele for iron (associated with lower iron status) and G is the risk allele for transferrin and transferrin saturation (associated with higher transferrin status and lower transferrin saturation status).
ALSPAC, Avon Longitudinal Study of Parents and Children; SNP, single nucleotide polymorphism.