Evaluation of Zinc Supplementation Effect on Fetal Outcomes in Pregnant Women with Lower-than-Median Serum Zinc Concentration

Zinc is the second main element in the body after iron. Its importance in pregnancy is related to role in DNA and protein synthesis and consequently the necessity of its availability for the appropriate growth and development of the fetus and neonate. The purpose of this study was to assess the effect of zinc supplement on fetal outcomes (height, weight, head and chest circumference of the fetus, low birth weight, and pre-term birth) in pregnant women with lower-than-median serum zinc. Participants of this experimental double-blind clinical trial study were 263 healthy singleton pregnant women with a mean age of 26.46 (±4.52) years and gestational age of 14.52 (±4.51) weeks whose (non-fasting) serum zinc levels were lower than median of the study population. All eligible individuals were randomly divided into two groups of zinc supplement and placebo. Individuals in the zinc supplement group (128 participants) took one zinc supplement capsule including 25 mg elemental zinc and participants in the placebo group (135 people) took one placebo capsule per day until the end of pregnancy. All women were under control and supervision until the end of the pregnancy and their information about labor, delivery, and neonate measures were collected through their obstetric records and then compared. Findings of this study showed no significant difference in fetal measures at birth (weight, height, head and chest circumference), pre-term delivery, and low birth weight between zinc supplement and placebo groups. According to our findings, administration of 25mg elemental zinc per day does not improve fetal measures in pregnant women with lower-than-median serum zinc concentration; however, more in-depth studies with larger sample sizes are recommended to achieve more reliable results.