Table 4A.

Associations between maternal serum ferritin concentrations at enrolment and pregnancy and infant outcomes

	Model 1b			Model 2c
Variablesa	n	β (SE) or RR (95%CI)	P-value	n	β (SE) or RR (95%CI)	P-value
Pregnancy outcomes
Birth weight, g	244	34.0 (30.5)	0.26	242	31.6 (30.1)	0.29
Low birth weight (<2500 g), n (%)	244	0.97 (0.70, 1.33)	0.83	242	0.96 (0.70, 1.32)	0.80
Gestational age at birth, weeks	250	0.14 (0.14)	0.32	248	0.17 (0.14)	0.22
Preterm (<37 weeks), n (%)	250	0.80 (0.57, 1.13)	0.21	248	0.77 (0.55, 1.09)	0.14
Preterm and low birth weight, n (%)	244	1.06 (0.63, 1.77)	0.83	242	1.02 (0.61, 1.71)	0.93
Small for gestational aged, n (%)	243	0.94 (0.77, 1.14)	0.54	241	0.93 (0.76, 1.14)	0.49
Infant outcomes
Haemoglobin, g/dl	68	0.18 (0.23)	0.42	68	0.25 (0.23)	0.28
Anaemia (<11.0 g/dl), n (%)	68	0.81 (0.61, 1.07)	0.13	68	0.82 (0.63, 1.08)	0.17
Length, cm	219	0.46 (0.20)	0.02	217	0.44 (0.20)	0.03
Length-for-age z-score (LAZ)	217	0.19 (0.10)	0.048	215	0.16 (0.10)	0.09
LAZ < −2	217	0.83 (0.67, 1.03)	0.09	215	0.86 (0.69, 1.08)	0.20
Weight-for-age z-score (WAZ)	243	0.07 (0.07)	0.35	241	0.06 (0.07)	0.36
WAZ < −2	243	0.92 (0.64, 1.33)	0.66	241	0.90 (0.63, 1.30)	0.58
Weight-for-length z-score (WLZ)	179	−0.10 (0.14)	0.46	177	−0.11 (0.14)	0.44
WLZ < −2	179	1.00 (0.69, 1.43)	0.98	177	1.03 (0.70, 1.50)	0.90
BMI z-score (BMIZ)	216	−0.13 (0.11)	0.25	214	−0.13 (0.11)	0.23
BMIZ < −2	216	1.05 (0.76, 1.44)	0.77	214	1.07 (0.78, 1.47)	0.68
Ponderal Index, g/cm3	218	−0.0006 (0.0004)	0.10	216	−0.0006 (0.0004)	0.09
Head circumference, cm	219	−0.03 (0.12)	0.78	217	−0.05 (0.12)	0.69
Chest circumference, cm	219	−0.03 (0.14)	0.85	217	−0.06 (0.15)	0.69
Waist circumference, cm	219	−0.06 (0.20)	0.75	217	−0.08 (0.20)	0.68
Hip circumference, cm	219	−0.16 (0.27)	0.55	217	−0.20 (0.28)	0.46
Mid-upper arm circumference, cm	217	0.37 (0.21)	0.08	215	0.38 (0.22)	0.08
Biceps skinfold, mm	218	0.05 (0.07)	0.45	216	0.05 (0.07)	0.48
Triceps skinfold, mm	218	−0.14 (0.10)	0.16	216	−0.15 (0.11)	0.15

^aSerum ferritin, natural log-transformed at enrolment (≤14 weeks gestation); beta (SE) is reported for continuous pregnancy outcomes; RR (95% CI) is reported for binary pregnancy outcomes

^bModels adjusted for gestational age of sample and vitamin B₁₂ intervention

^cModels adjusted for gestational age of sample, vitamin B₁₂ intervention, maternal BMI, standard of living index (SLI) >28, educational level, and ln(CRP)

^dSmall for gestational age (SGA) was defined as birth weight < 10th percentile of the gestational age, using INTERGROWTH reference [17]