Vol.:(0123456789) 1 3 World Journal of Pediatrics https://doi.org/10.1007/s12519-019-00305-8 META-ANALYSIS Cord blood zinc status efects on pregnancy outcomes and its relation with maternal serum zinc levels: a systematic review and meta‑analysis Sevginur Akdas 1  · Nuray Yazihan 1,2 Received: 28 May 2019 / Accepted: 6 August 2019 © Children’s Hospital, Zhejiang University School of Medicine 2019 Abstract Background The association between maternal and cord blood zinc level and pregnancy outcomes remains uncertain. The present study aims to assess whether maternal blood zinc level represents cord blood zinc level correctly. Methods In this meta-analysis, systematic search was performed in PubMed, Web of Science, and Scopus databases for relevant available English articles which included mean and standard deviation values of cord blood zinc level up to April 2019. For the assessment of the relation between cord blood zinc level and pregnancy outcomes, the pooled standard mean diference with 95% confdence interval (CI) was used and 23 studies were analyzed. Results Cumulative analysis showed that cord blood zinc level was found signifcantly decreased in pregnancies with complications compared with healthy pregnancy controls [REM: P = 0.0007, mean diference − 7.9 (− 12.48, − 3.31)]. For further analysis, maternal serum zinc level status was determined from same studies to compare with cord blood levels and subgroups were detected as “Preterm”, “Preeclampsia”, “Small for gestational age/Intrauterine growth restriction and Low birth weight”. It was observed that cord blood zinc levels in subgroup analysis were also decreased and/or tend to be decreased compared to healthy pregnancies, except for preeclampsia subgroup. Also, a correlation was seen between cord blood and maternal blood zinc level status (R = 0.4365, 95% CI − 0.530, 0.756; P = 0.0351). Conclusion It was thought that cord blood zinc level might tend to decrease more than maternal serum zinc level in the pathological conditions during pregnancies. Keywords Intrauterine growth restriction · Preeclampsia · Pregnancy · Preterm · Zinc Introduction Zinc is known as one of the essential trace elements to main- tain the basic physiological functions of the human body. It is important for maternal period because of its efects on fer- tility, growth, and development of fetus and newborn. Zinc plays roles on body homeostasis through many enzymes, proteins, and metabolic pathways. Especially in fetus and newborn, it is essential for visual functions, immune and thymic activity, neurotransmission, proliferation, cellular growth, and intestinal ion transportation [1]. A healthy preg- nant woman should maintain maternal-fetal zinc cycle with dietary zinc intake. To achieve zinc homeostasis in preg- nancy, it was stated that there was an increase in zinc absorp- tion and a decrease in urinary excretion. This situation could be mentioned as control mechanism for the inadequacy of zinc intake or the increased need during pregnancy [2]. Also it is known that zinc defciency during pregnancy may cause fetal malformations, embryonic and fetal deaths, fetal growth retardation or pregnancy or birth complications that threaten maternal or fetal life [3]. Maternal serum zinc levels were investigated in diferent studies. In the study of Keshavarz et al., zinc, copper, and superoxide dismutase activity and lipid profles were inves- tigated in the sera of 100 preeclampsia and 100 healthy preg- nant women. As a result of the study, while zinc and copper values were found signifcantly lower in the patient group * Nuray Yazihan nurayyazihan@yahoo.com 1 Interdisciplinary Food, Metabolism and Clinical Nutrition Department, Institute of Health Sciences, Ankara University, Ankara, Turkey 2 Department of Pathophysiology, Internal Medicine Division, Faculty of Medicine, Ankara University, Ankara, Turkey