Research
Maternal Anemia and Its Correlation with the Oxidative Stress in Cord Blood
*Monika Dubey *, Anuradha Khanna *Ruchi Sinha
- *Department of Obstetrics & Gynecology, Institute of Medical Sciences, Banaras Hindu University, Varanasi-221005, India
- Submitted: : March 1, 2013
- Accepted: March 23, 2013
- Published: March 25, 2013
Background
To find out the effect of maternal anemia on oxidative stress in neonate and to correlate oxidative stress with severity of maternal anemia and birth weight.
Methods
A prospective cohort study in anemic pregnant women attending the antenatal clinic and emergency services in S.S Hospital, Banaras Hindu University, Varanasi, India.
The oxidative stress was determined by measuring the levels of the antioxidant enzymes viz. Glutathione Peroxidase, Catalase and Superoxide dismutase in the cord blood.
Results
The level of antioxidant enzymes Superoxide dismutase, Catalase and Glutathione Peroxidase in cord blood showed a decreasing trend with the increase in the severity of maternal anemia. The differences were statistically significant (p<0.001) for all these enzymes in relation to maternal Hemoglobin subgroups. The levels were also significantly correlated with birth weights.
Conclusion
The antioxidant enzymatic capacity of new born decreases with severity of maternal anemia which may lead to various free radicals mediated fetal injuries.
Keywords
Oxidative Stress, Anemia, Glutathine Peroxidase (GSH-Px), Catalase, Superoxide Dismutase (SOD)
Introduction
Oxidative stress is an imbalance between maternal pro-oxidants and antioxidants. Oxidative stress presents numerous opportunities for tissue injury through formation of reactive oxygen/nitrogen species and free radicals. The generation of free radical is a normal physiological process and are essential for cell aerobic metabolism and fetal growth, but they are toxic when overproduced, resulting in an attack of all classes of biological macromolecules, polysaccharides, nucleic acid, lipids and proteins [1]. The cells have evolved a number of counter acting antioxidant defenses. These antioxidant defense mechanisms include the free radical scavenging antioxidant enzymes like Superoxide dismutase (SOD), Glutathione peroxidase (GSH-Px) and Catalase, which limit the cellular concentration of free radicals and prevent excessive oxidative damage [2].
Pregnancy, mostly because of the mitochondria-rich placenta,is a condition that favors oxidative stress. Behne [3] and Pathak et al [4] have shown that there is a progressive fall in the activity of plasma Glutathione peroxidase and superoxide dismutase as pregnancy advanced. The role of oxidative stress has been implicated in the pathogenesis of many obstetrical complications like Pre-eclampsia, Gestational diabetes mellitus, Fetal Growth restriction and Preterm delivery [5 8]. The consequence of oxidative stress on fetal structure involves the activation of a complex array of genes involved in inflammation, coagulation, fibrinolysis, cell-cycle apoptosis and signal transduction and as a consequenceFR reactions may induce a wide range of biological toxic effects [9].Complications of the newborns such as bronchopulmonary dysplasia, retinopathy of prematurity, subependymal and intraventricular hemorrhage and necrotizing enterocolitis are thought to be due to the increased susceptibility of the newborns to free radical injury [8]. Buonocore G et al (2002) found thattotal hydroperoxides and advanced oxidative proteinproducts increased from birth to seven days of life inboth preterm and term babies, indicating that an OSoccur early in life and newborns are particularly susceptibleto oxidative damage [10].
Oxidative stress worsens with anemia in most of the animal and human studies [11 12]. Anemia is the most common medical disorder of pregnancy. Anemia is one of the important causes of direct maternal death. In 47% of maternal deaths in developing countries it is an indirect cause of death (ICMR 2000).
Our study is an attempt to asses oxidative stress in cord blood of newborns and to correlate it with severity of maternal anemia and birth weight.
Material and methods
This prospective cohort study was conducted on 200 pregnant women with anemia admitted in Department of Obstetrics and Gynecology, Institute of Medical Sciences, Varanasi, India. Selection criteria: Patients attending the antenatal clinic were evaluated and screened and those who fulfilled the criteria for anemia, as defined by WHO (Hemoglobin<11gm/dl), were taken as cases, Patients having medical complications like chronic hypertension, renal disease and diabetes were excluded. Cases were further classified on the basis of severity of anemia according to Indian Council of Medical Research (ICMR) (Box 1).Hematological and Biochemical tests were performed to know the severity, type and etiology of anemia. The levels of the antioxidant enzymes viz. Glutathione Peroxidase, Catalase and Superoxide dismutase were determined in the maternal and cord blood.
|
Category
|
Anemia Severity
|
Hemoglobin
(gm/dl)
|
|
1.
|
Mild
|
10.0-10.9
|
|
2.
|
Moderate
|
07.0-9.9
|
|
3.
|
Severe
|
< 7.0
|
|
4.
|
Very Severe
(Decompensated)
|
< 4
|
Assay of Glutathione Peroxidase
The glutathione determination was performed by the method described by Beutler et al (1963) [13] using 5, 5’-dithio bis-(2-nitrobenzioic acid). This method is based on the development of relatively stable yellow colour when 5, 5'-dithiobis (2-nitrobenzoic acid) reagent is added to sulfahydril compound.
Assay of catalase
Serum catalase activity was measured by decomposition of hydrogen peroxide by the method of (Aebi, 1973) [14].
Assay of superoxide dismutase
Superoxide dismutase was assayed by the method described by Marklund and Marklund (1974) [15] using pyragallol. SOD assay is based on the ability of the enzyme to inhibit the auto oxidation of pyragallol.
Statistical Analysis
The statistical analysis was done by ANOVA to find out the significant difference between groups. One way analysis of variance “F” test and multiple range test (SNK-Student's Newman Kuel Test) were applied to test the significance of difference among the mean of the different groups. According to the distribution of data, parametric and nonparametric tests have been used.
Results
A total of 200 anemic pregnant patients were studied. The patients belong to age group of 18 years to 35 years with maximum i.e. 62.5% in 21-25 years. Most of the anemic cases (117) were primigravida while 83 anemic cases were multigravida.
The patients were distributed according to the severity of anemia (ICMR Grading). Maximum cases (71%) belong to moderate anemia (Hb 7-9.9 gm %). 23% cases were having mild anemia (Hb 10-10.9gm/dl) while 5% and 1% of cases were having severe (Hb 4-6.9 gm/dl) and very severe anemia (Hb< 4gm/dl). Cases were also distributed according to MCV and MCH levels. 66% patients were having microcytic hypochromic anemia.
Anemia was classified according to etiology i.e. iron deficiency anemia, megaloblastic anemia, diamorphic anemia and hemolytic anemia. Nutritional anemia was the commonest cause of anemia in pregnancy. Iron deficiency being the commonest cause (88%).
The patients having hemolytic anemia (24 cases) were investigated to find out the specific cause for hemolysis (Table 1). Congenital causes for hemolytic anemia include thalassemia trait, Sickle cell trait, HbD trait and HbE trait. Autoimmunity was responsible for the acquired hemolytic anemia.
|
Type of hemolytic anemia
|
Number
|
Percentage
(n=200)
|
|
Congenital
|
|
Thalassemia trait
|
12
|
6
|
|
Sickle cell trait
|
4
|
2
|
|
Hb D trait
|
2
|
1
|
|
Hb E trait
|
2
|
1
|
|
Hereditary spherocytosis
|
2
|
1
|
|
Acquired
|
Autoimmune
|
2
|
1
|
The levels of the antioxidant enzymes viz. Glutathione Peroxidase (GSH-Px), Catalase and Superoxide dismutase (SOD) were analyzed in the cord blood and correlated with the severity of anemia i.e. Hemoglobin gm/dl and baby birth weight.
The data in (Table 2) showed that the levels of SOD, GSH-Px and Catalase in cord blood significantly decreased with drop in maternal Hemoglobin levels irrespective of body weight of offspring. Further the difference was statistically significant in various subgroup of maternal Hemoglobin in anemic mothers (Table 2).
|
Hb (gm/dl)
|
SOD Mean
(units/mg protein) ± SD
|
GSH-Px
Mean (units/mg protein) ± SD
|
Catalase Mean
(units/ mg protein) ± SD
|
|
I.<6.9 (n=86)
|
0.56±0.06
|
1.11±0.069
|
102.62±0.94
|
|
II. 7.0-9.9 (n=63)
|
0.73±0.06
|
1.22±0.096
|
107.66±1.32
|
|
III. 10.0-10.9 (n=51)
|
0.82±0.01
|
1.26±0.035
|
110.33±0.81
|
The data in (Table 3) shows that there is significant increase in activity of SOD, GPX and Catalase in cord blood in relation to increase in birth weight of offspring irrespective of maternal Hemoglobin status. The differences between various subgroup of body weight were also statistically significant (Table 3).
|
Birth weight (gms)
|
SOD (units/mg protein)± SD
|
GSH-Px Mean
(units/mg protein) ± SD
|
Cord blood Mean
(units/mg protein) ± SD
|
|
I<2000
(n=86)
|
0.67±0.07
|
1.11±0.069
|
106.12±1.74
|
|
II. 2001-2250 (n=63)
|
0.78±0.03
|
1.22±0.096
|
108.77±0.69
|
|
III. 2251-2500 (n=51)
|
0.81±0.08
|
1.26±0.035
|
110.13±0.90
|
Q values For SOD: I vs II: 12.85***, I vs III: 15.51*** II vs III: 3.22*For GSH-Px: I vs II: 9.633***, I vs III: 12.07***, II vs III: 2.99*For Catalase: I vs II: 12.619***, I vs III: 17.434***, II vs III: 5.66***p<0.05; **p<0.01; ***p<0.001
Since, the increases in levels of these antioxidant enzymes were significant in relation to increase in birth weight and maternal Hemoglobin. Therefore multiple correlation and regression analysis was done in order to find out independent influence of Hemoglobin and birth weight on activity of enzymes. Although both the factors exert their independent influence, however maternal Hemoglobin levels were found to have profound influence as suggested by R2 values and partial r value.
Discussion
The present study has been conducted to see the oxidative stress in new born due to maternal anemia. For this the activity of three antioxidant enzymes viz., Superoxide dismutase (SOD), Glutathione Peroxidase (GPX) and Catalase were studies in the cord blood.
The activities of these antioxidant enzymes namely SOD, Catalase and GPX in cord blood showed a decreasing trend with the increase in the severity of maternal anemia. Hence it can be concluded that there is rising oxidative stress in newborns with increasing severity of maternal anemia. However, only SOD and Catalase in cord blood have independent significant correlation with baby weight. The multiple R and partial r correlation suggested that maternal Hb had profound influence on these enzymes as compared to body weight of the offspring. As far as could be ascertained, no comparable study is available in the literature.
In recent years, the role of decreasing antioxidants and increasing superoxides is gaining importance as they are threat for the normal pregnancy. We found the decreasing antioxidant capacity of newborn from the very beginning of life with the severity of maternal anemia. A very delicate balance between the oxidant and antioxidant mechanism is essential to protect the fetus from suffering the ill effects of free oxygen radicals. Free radical reactions lead to DNA damage (fragmentation, apoptosis, base modifications and strand breaks), to lipid, protein and polysaccharides oxidation and as a consequence Free radical reactions may induce a wide range of biological toxic effects [16].
Some antioxidants not only detoxify free radicals but also have anti-inflammatory properties [17]. With the increasing realization that correction of anemia along with antioxidants may indeed be helpful in preventing and possibly reducing the severity of free radical mediated injuries in new born, a whole new era for management seems to have opened up.
Conclusions
The antioxidant enzymatic capacity of new born decreases with severity of maternal anemia which may lead to various free radical mediated fetal injuries. The prenatal prophylactic use of antioxidants could help to reduce oxidative stress related diseases in fetuses and newborns.
Conflict of interest
The authors declare that they have no competing interests.
Author’s Contribution
MD: Concept andAnalysis of cases study
AK: Concept and design of study
VS: Analysis of study and preparation of manuscript
Ethical Considerations
The study was approved by the institute ethics committee.
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