Serum micronutrient levels, nucleic acid metabolism and antioxidant defences in pregnant Nigerians: implications for fetal and maternal health.

Abstract

Micronutrients regulate numerous metabolic processes in pregnancy but their possible antioxidant function and contributions of alterations in their metabolism to fetal and maternal morbidity and mortality have received insufficients attention. Scrum levels of copper, manganese and zinc were determined in 40 pregnant Nigerian women spread across the three trimesters of pregnancy and compared with those of 25 non-pregnant women of similar demographic and anthropometric characteristics. Scrum levels of uric acid were also determined in both groups of women. The mean scrum levels of manganese and zinc were significantly lower in the pregnant than in the non-pregnant state (P<0.02, P<0.002), respectively. Unlike manganese and zinc, copper was significantly elevated in the pregnant than in the non-pregnant state. The endogenous anti-oxidant, uric acid, was also significantly reduced in the pregnant than in the non pregnant state (P<0.001). Copper levels increased progressively in all the three trimesters of pregnancy compared with controls (P<0.001). However, zinc levels declined steadily in all the 3 trimesters, but only the level of the third trimester was significantly different from the non-pregnant state (P<0.05). Unlike zinc, uric acid rose consistently in all the 3 trimesters compared with the non-pregnant state. Manganese and uric acid were significantly more elevated in the third than the first trimester. One way analysis of variance (ANOVA) and multiple comparisons (Tukcy HSD) show that the differences in the antioxidant levels can be ascribed mainly to the second and third trimesters. The prevalence of zinc deficiency was 4.0% in the non pregnant state as compared to 22.5% in the pregnant subjects. The implications of micronutrient deficiencies and associated antioxidant status in pregnancy arc discussed. Considering their role in pregnancy, prevention of such deficiencies and attendant oxidative stress may contribute to a reduction in the incidence of fetal and maternal ill-health, and complications of pregnancy. Interventions should be aimed mainly at the second and third trimesters