Effects of parity on antioxidant status in pregnant women in a Nigerian population

Abstract

Background: Controversial reports on the effects of multiparity on pregnancy outcome have been documented in literature. While some authors have strongly supported the popular belief that multiparity is associated with complicated pregnancy outcome, others have claimed that there is no association. Moreover, little or no information has been documented about the effect of multiparity on antioxidant status of pregnant women in Nigeria. This is the purpose of this study. Methods: The study involved a total of one hundred and fourteen (114) subjects which were randomly selected, this comprises of thirty seven (37) non pregnant women as control subjects and seventy seven (77) pregnant women as test subjects, with different parity status and all within the ages 15-50 years. All the subjects had normal blood pressure (not more than 125/80mmHg).The test subjects were all in the third trimester with no underlying disease and not on any chronic drug therapy. They were grouped into five groups according to their parity status. Plasma estimations of their vitamin C, vitamin E, albumin, uric acid, selenium, copper, and zinc were determined; and the control group results compared with the test group results. The results showed that the albumin concentration of the test group was significantly lower than those of the control group (p<0.001), and amongst the test sub-groups the albumin was significantly reduced in the multipara (p<0.001). Results: The reverse was observed for plasma uric acid, where there was an increase in the test group than the control (p<0.001) and the increase was more in the multipara in the test group. For the vitamins; Plasma vitamin E concentration was significantly decreased in the test group than in the control group and the decrease was more as parity increased. However, vitamin C in all the six groups (control group and all the test subgroups) was not significantly different from one another (p<0.149). For the minerals (trace elements); copper showed no statistically significant difference (p<0.143) among the groups. Selenium concentration was observed to be significantly decreased (p<0.001) in the test group than the control and the decrease was more in the multipara. Lastly, zinc was obviously less in test group than control group and the reduction was more as parity increased (p<0.001). Conclusion: Conclusively, the results indicated that pregnancy significantly reduced the serum levels of some of the antioxidants such as albumin, vitamin E, selenium and zinc. The reduction in each of these analytes was more pronounced in multiparity than in low parity or primip and this is an indication that multiparity causes more oxidative stress. While vitamin C and copper levels were not significantly affected by pregnancy or multipartiy, uric acid level increased in pregnancy and this increase was more in multipara than in low parity or primp. The increase in uric acid however may be due to effect of pregnancy or multiparity on the kidney. It is suggested from the findings of this study that food supplements rich in antioxidant substances (vitamin E, albumin, zinc, and selenium) will be beneficial in pregnancy, especially in the multiparous, this may reduce oxidative stress and hence reduce complications of pregnancy as well as reduce maternal mortality, hence improve safe motherhood.