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 ?
Maternal zinc supplementation does not affect size at birth or pregnancy duration in Peru.
To estimate the effect of maternal zinc deficiency on pregnancy outcomes , we conducted a zinc supplementation trial in an urban shantytown in Lima , Peru , a population with habitual low zinc intakes . Beginning at 10 - 24 wk gestation , 1295 mothers were r and omly assigned to receive prenatal supplements containing 60 mg iron and 250 ( g folate , with or without 15 mg zinc . Women were followed up monthly during pregnancy . At birth , newborn weight was recorded , and crownheel length , head circumference and other circumferences and skinfold thicknesses were assessed on d 1 . At delivery , 1016 remained in the study ;  duration of pregnancy  was known for all women , and birth weight information was available for 957 newborns . No differences were noted in duration of pregnancy ( 39.4 + /- 2.2 vs. 39 . 5 + /- 2.0 wk ) or birth weight ( 3267 + /- 461 vs. 3300 + /- 498 g ) by prenatal supplement type ( iron + folate + zinc vs. iron + folate ; P > 0.05 ) , and there were no differences in the rates of preterm ( < 37 wk ) or post-term ( > 42 wk ) delivery , low birth weight ( < 2500 g ) or high birth weight ( > 4000 g ) . Finally , there were no differences by prenatal supplement type in newborn head circumference , crownheel length , chest circumference , mid-upper arm circumference , calf circumference or skinfold thickness at any of three sites . Adjustment for covariates and confounding factors did not alter these results . Adding zinc to prenatal iron and folate tablets did not affect duration of pregnancy or size at birth in this population
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 ?