Study of relationship between zinc levels and fetus weight at term

الملخص EN

Objective: Prospective observational study about the relationship between zinc levels (maternal and fetal plasma and amniotic fluid levels and umbilical cord concentration) and fetal weight at term.

Methods: The study started screening a group of pregnant women in AUHOG and El-Shahbaa Medical Center of SARC, to determine zinc deficiency and to choose the candidate to the next part of study.

Inclusion criteria were fetuses of healthy mothers without any risk factor for LBW so we had 60 cases, all measurements was done at term during an elected CS before umbilical cord cut, hence we got simultaneously a sample from maternal and fetal blood, amniotic fluid, then we had a piece of umbilical cord, then the newborn was assessed fully.

Results: Zinc deficiency rate was 70.43% (324 out of 460 mothers), mean weight was 2921±517 g, mean value of maternal serum zinc was 0.274±0.057 μg/ml, whereas mean fetal serum zinc levels was 0.98±0.68 μg/ml, but zinc deficiency appear with severe maternal zinc deficiency, and mean zinc values in amniotic fluid was 5.9±2.58 μg/ml.

Considering the relationship between maternal serum zinc levels and birth weight we found a positive relation (r=0.87).

Considering the relationship between fetal serum zinc levels and birth weight we found a positive relation (r=0.73).

Considering the relationship between amniotic fluid zinc levels and birth weight we found a moderate positive relation (r=0.69).

Mean umbilical cord zinc concentration was 98.418±68.1 μg/g.

Considering the relationship between cord tissue zinc concentrations and birth weight we found a positive relation (r=0.90).

Odds ratio for LBW in mild to moderate maternal zinc levels was so low (0.6), and that means that it does not affect birth weight, whereas odds ratio for LBW in severe maternal zinc levels was very high (12.2) and that means that severe maternal zinc deficiency is a risk factor for LBW.

Conclusions: Zinc is one of the most important mineral elements for fetal growth and there is a direct relation between its maternal serum levels and fetal serum levels, amniotic fluid levels and umbilical cord tissue concentration, hence they are affected by severe maternal zinc deficiency (less than 0.18 μg/ml elevates LBW risk by 12 fold.