Table 4.

Adjusted associations of maternal blood and hair (log₁₀) Mn concentrations during pregnancy with fetal growth (among term births)^a and length of gestation stratified by gestational anemia, ISA study, Costa Rica, 2010-2011 (n = 380).

Outcome	Mean blood Mn (μg/L)b,c			Mean hair Mn (μg/g)d,e
	n	β (95% CI)	p INT	n	β (95% CI)	p INT
Birth weight (g)
No gestational anemia	205	6.2 (−2.2,14.5)	0.32	195	42.8 (−76.5,162.2)	0.99
Gestational anemia	146	−3.1 (−14.4,8.1)		136	27.2 (−106.8,161.2)
Body length (cm)
No gestational anemia	204	0.00 (−0.05,0.05)	0.95	193	−0.22 (−0.90,0.47)	0.92
Gestational anemia	143	−0.01 (−0.07,0.05) #		133	−0.08 (−0.83,0.67)
Ponderal index (g/cm3)
No gestational anemia	204	0.01 (0.00,0.01)	0.31	193	0.09 (−0.01,0.19) *	0.66
Gestational anemia	143	0.00 (−0.01,0.01)		133	0.02 (−0.07,0.11) #
Head circumference (cm)
No gestational anemia	202	0.00 (−0.03,0.03)	0.24	191	0.11 (−0.31,0.52)	0.52
Gestational anemia	141	−0.03 (−0.07,0.02)		132	−0.24 (−0.75,0.26)
Chest circumference (cm)
No gestational anemia	82	−0.02 (−0.07,0.04)	0.75	83	1.19 (0.43,1.95) **	0.14
Gestational anemia	71	−0.04 (−0.10,0.03)		71	0.39 (−0.32,1.10)
Length of gestation (days)
No gestational anemia	223	−0.06 (−0.33,0.21)	0.49	213	0.38 (−3.50,4.25)	0.92
Gestational anemia	152	−0.17 (−0.54,0.21)		139	1.05 (−2.87,4.97)

Abbreviations: CI, confidence interval.

^aModels for birth weight, body length, ponderal index, head circumference, and chest circumference include only term births.

^bResults are for each one-unit increase in blood Mn concentrations.

^cAdjusted for maternal education, parity, smoking during pregnancy, pre-pregnancy body mass index, infant sex, gestational diabetes, caffeinated tea intake during pregnancy, and timing of prenatal care initiation. Models for birth weight, body length, ponderal index, head circumference, and chest circumference also adjusted for length of gestation and length of gestation squared.

^dResults are for each 10-fold increase in hair Mn concentrations.

^eAdjusted for maternal education, parity, smoking during pregnancy, pre-pregnancy body mass index, infant sex, maternal country of birth, vaginal bleeding in the first trimester of gestation (m = 28, 7.4%), caffeinated tea intake during pregnancy, iron intake during pregnancy, and maternal age. Models for birth weight, body length, ponderal index, head circumference, and chest circumference also adjusted for length of gestation and length of gestation squared.

^*p_Linear < 0.10

^**p_Linear < 0.05

^#p_GAM < 0.05