We hypothesize , therefore , that zinc homeostatic adjustments during pregnancy and lactation improve zinc utilization sufficiently to provide the increased zinc needs in these stages and , therefore , mitigate immediate detrimental effects due to a low zinc intake .
Zinc plays critical roles during embryogenesis , fetal growth , and milk secretion , which increase the zinc need for pregnancy and lactation .
Increased needs can be met by increasing the dietary zinc intake , along with making homeostatic adjustments in zinc utilization .
Potential homeostatic adjustments include changes in circulating zinc , increased zinc absorption , decreased zinc losses , and changes in whole body zinc kinetics .
Although severe zinc deficiency during pregnancy has devastating effects , systematic review s and meta- analysis of the effect of maternal zinc supplementation on pregnancy outcomes have consistently shown a limited benefit .
The specific questions addressed are the following : How is zinc utilization altered during pregnancy and lactation ?
Are those homeostatic adjustments influenced by maternal zinc status , dietary zinc , or zinc supplementation ?
The effect of zinc supplementation on pregnancy outcome.
OBJECTIVE To evaluate whether zinc supplementation during pregnancy is associated with an increase in birth weight . DESIGN A r and omized double-blind placebo-controlled trial . SETTING Outpatient clinic and delivery service at the University of Alabama at Birmingham . PATIENTS Five hundred eighty medically indigent but otherwise healthy African-American pregnant women with plasma zinc levels below the median at enrollment in prenatal care , r and omized at 19 weeks ' gestational age . Women were subdivided by the population median body mass index of 26 kg/m2 into two groups for additional analyses . INTERVENTION Women who were taking a non-zinc-containing prenatal multivitamin/mineral tablet  were r and omized to receive either a daily dose of 25 mg of zinc or a placebo until delivery . MAIN OUTCOME MEASURES Birth weight , gestational age at birth , and head circumference at birth . RESULTS In all women , infants in the zinc supplement group had a significantly greater birth weight ( 126 g , P = .03 ) and head circumference ( 0.4 cm , P = .02 ) than infants in the placebo group . In women with a body mass index less than 26 kg/m2 , zinc supplementation was associated with a 248-g higher infant birth weight ( P = .005 ) and a 0.7-cm larger infant head circumference ( P = .007 ) . Plasma zinc concentrations were significantly higher in the zinc supplement group . CONCLUSIONS Daily zinc supplementation in women with relatively low plasma zinc concentrations in early pregnancy is associated with greater infant birth weights and head circumferences , with the effect occurring predominantly in women with a body mass index less than 26 kg/m2
We hypothesize , therefore , that zinc homeostatic adjustments during pregnancy and lactation improve zinc utilization sufficiently to provide the increased zinc needs in these stages and , therefore , mitigate immediate detrimental effects due to a low zinc intake .
Zinc plays critical roles during embryogenesis , fetal growth , and milk secretion , which increase the zinc need for pregnancy and lactation .
Increased needs can be met by increasing the dietary zinc intake , along with making homeostatic adjustments in zinc utilization .
Potential homeostatic adjustments include changes in circulating zinc , increased zinc absorption , decreased zinc losses , and changes in whole body zinc kinetics .
Although severe zinc deficiency during pregnancy has devastating effects , systematic review s and meta- analysis of the effect of maternal zinc supplementation on pregnancy outcomes have consistently shown a limited benefit .
The specific questions addressed are the following : How is zinc utilization altered during pregnancy and lactation ?
Are those homeostatic adjustments influenced by maternal zinc status , dietary zinc , or zinc supplementation ?