Oxygen undergoes extensive metabolism that
can result in the production of toxic derivatives.
Activated molecular species derived from oxygen
metabolism are designated as reactive oxygen species
A cross-sectional study was carried out in 50 women who received antenatal and obstetric care at Perinatology Unit of Zekai Tahir Burak Women Health Education and Research Hospital between January and May 2011. This study was approved by The Medical Ethics Committee of the hospital, and informed consent was obtained from all of the participants. Subjects were eligible for enrollment if they were between 16 and 45 years of age. Gestational age was evaluated on the basis of the last menstrual period and confirmed by ultrasound. Patients were divided into two groups.
The first group included 25 pregnant women at less than 10 weeks’ gestation with light, intermittent, painless vaginal bleeding. This was determined by the clinical history and clinical examination which included gynecologic examination and trans-vaginal ultrasonography. All these ended in an uneventful pregnancy at term, with a normal baby. Complete bed-rest at home was recommended in all cases with vaginal bleeding. All patients were followed at 7 day intervals clinically, including bimanual examination and sonographically, until the bleeding stopped.
The second group consisted of 25 patients at less than 10 weeks of gestation with normal ongoing pregnancies. The pregnant controls were selected from the ones at less than 10 gestational weeks with no pre-existing complications. A gestational sac with fetal heart rate was identified by trans-vaginal ultrasonography. All of the patients in the control group were matched for age, gestational age and body mass index (BMI).
Exclusion criteria were as follows: gestational age after 10 weeks (based on the 1st day of the last menstrual period; n=3), history of recurrent spontaneous miscarriages (defined as three or more consecutive pregnancy losses; n=2), history of documented chromosomal abnormalities, endocrine diseases (n=2), internal diseases, connective tissue diseases, hypertension, coagulopathies, multiple pregnancies (n=1), smoking (n=1), diabetes mellitus, and anemia (n=2). A total of 61 patients were screened, but 50 (81.96%) of them met our selection criteria.
All blood samples were obtained before administration of any medication and before any medical or surgical intervention. Serum was separated by centrifugation at 4000 g for 10 minutes and frozen at -70˚C for later analysis. Serum TAC and TOS levels were assayed using a Hitachi 912 analyzer (Roche Diagnostics, Geneva, Switzerland).
Serum TAC was determined using an automated
measurement method, developed by Erel (
Serum TOS was determined using a novel automated
measurement method, developed by Erel
The SPSS package for windows version 15.0 software (SPSS Inc, Chicago, IL, United States) was used to perform statistical analyses. Distribution of the groups was analyzed with one sample Kolmogrov-Smirnov test. All data were distributed normally. Students’ two-tailed-t test was used for the assessment of differences between groups. A probability p value of <0.05 was considered statistically significant.
Details of pregnancies including gestational
age and BMI are shown in table 1. There were no
statistically significant differences between two
groups regarding maternal age, number of pregnancies,
gestational age and BMI (
Maternal serum TAC levels were significantly
lower in pregnancies with vaginal bleeding
compared to controls (p=0.001), whereas TOS
values were significantly higher in pregnancies
with vaginal bleeding than controls (p=0.001,
Baseline characteristics and output data of the women
|Characteristics||Study group (n=25)||Control group (n=25)||P value|
|29.48 ± 5.46||28.56 ± 5.47||0.555|
|24.76 ± 4.02||23.11 ± 4.41||0.173|
|2 (1-6)||2 (1-5)||0.308|
|8.13 ± 1.87||8.46 ± 2.93||0.635|
|1.16 ± 0.20||1.77 ± 0.08||0.001|
|4.01 ± 0.20||2.57 ± 0.65||0.001|
*; Values are mean ± SD, **; Values are median (range)
SD; Standard deviation, BMI; Body mass index, TAC; Total antioxidant capacity and TOS; Total oxidant status.
The current study showed that serum TOS levels
were higher and serum TAC levels were lower in
pregnant women with vaginal bleeding when compared
to women with normal-ongoing pregnancies
of similar gestational age in the first trimester.
Vaginal bleeding is common complication in the
first trimester of pregnancies and may be an early
marker for placental dysfunction. About half of patients
presenting with bleeding have miscarriage
Antioxidants can exist in enzymatic and nonenzymatic forms. Common enzymatic defenses include superoxide dismutase (SOD), catalase, and glutathione peroxidase and glutathione reductase. Nonenzymatic agents are ferritin, ceruloplasmin, transferin, ascorbic acid (vitamin C), and [alpha]- tocopherol (vitamin E).
A previous study by Ozkaya et al. (
In the present study decreased serum total antioxidant
capacity levels and increased serum total oxidant
status in the pregnant women at less than 10 weeks of
gestation with light vaginal bleeding compared with
the normal pregnant women were determined using
a novel automated measurement method (
There are several limitations of our study. The sample size of the study is relatively small and the design is cross-sectional in nature. Moreover it is difficult to justify the role of antioxidant supplementation in the prevention of ROS- induced damage, as none of our subjects received vitamin supplementation before or in the early weeks of their pregnancies. A third group of women with vaginal bleeding ending with abortion can be evaluated and this examination could help to determine whether there is a cut off level for TOS and TAC in early pregnancy which discriminates between viable and non-viable pregnancy.
The possible subsequent outcomes associated with oxidant/antioxidant imbalance in early pregnancies with vaginal bleeding remain to be established. Further well-designed randomized control studies are needed to determine a threshold value for TOS and TAC levels. Also the effectiveness of antioxidant supplementation in reversing spontaneous abortions needs to be established.