Maternal Serum Concentrations of Selenium, Copper and Zinc during Pregnancy are associated with Risk of Spontaneous Preterm Birth: A case-control study from Malawi

Preterm birth is delivery before 37 completed weeks. A study was conducted to evaluate the association of maternal serum concentrations of selenium, copper, and zinc, and preterm birth. There were 181 women in this nested case-control study, 90/181 (49.7%) term and 91/181 (50.3%) preterm pregnant women. The overall mean serum concentration of selenium was 77.0; SD 19.4µg/L, copper was 2.50; SD 0.52 mg/L and zinc was 0.77; SD 0.20 mg/L with reference values of 47-142µg/L, 0.76-1.59mg/L and 0.59-1.11 mg/L, respectively. For preterm birth, mean serum concentrations for selenium was 79.7; SD 21.6µg/L, copper was 2.61; SD 0.57 mg/L, and zinc was 0.81; SD 0.20 mg/L compared to that of term births: selenium (74.2; SD 16.5µg/L; p=0.058), copper (2.39; SD 0.43 mg/L; p = 0.004), and zinc (0.73; SD 0.19 mg/L; p = 0.006) respectively. In adjusted analysis, every unit increase in maternal selenium concentrations gave increased odds of being a case OR 1.01 (95% CI: 0.99; 1.03), p=0.234, copper OR 1.62 (95% CI: 0.80; 3.32); p = 0.184, zinc OR 6.88 (95% CI: 1.25; 43.67); p=0.032. Results show that there was no deficiency of selenium, and zinc; and high serum concentrations of copper in pregnancy. Preterm birth was associated with higher maternal serum concentrations of copper and zinc.