International Journal of Medical Laboratory

Introduction
Each year hundreds of women die due to the complications of pregnancy and delivery [1], 16% percent of whom are nearly because of preeclampsia followed by hypertension in pregnancy; nevertheless, its leading cause is not yet known [2]. This process is aggravated following the increase in venous thrombosis and antigenic and antibody reactions between the level of mother’s blood cells and that of the fetus [3]. The blood group types are regarded as a risk factor in coagulation disorders [4], and it seems that there is a relationship between preeclampsia and coagula-tion disorders. Moreover, pregnancy increases blood changes which consequently increase the possibility of undesirable pregnancy outcomes such as miscarriage and venous thrombosis [5]. In one study, it was observed that there is a significant relationship between mothers’ blood type and frequent miscarriages [6]. Therefore, it seems that blood type is a factor affecting vascular lesions and its respective outcomes. Accordingly, this study was carried out to investigate the relationship between the ABO blood group and preeclampsia.
Materials and Methods
Through a case-control study, a comparison was made between the blood type of 50 women with preeclampsia and 50 healthy women. The sample included all women referring to the midwifery clinic in Gonabad city. The samples were then assigned by census samppling method into two groups . The control group consisted of women who had experienced one delivery without hypertension and those who had preeclampsia characterized by blood pressure C140/90 mmHg and proteinuria repeatedly ≥ 0.3 g/l or ≥ 0.5 g/24 hours or dipstick ≥+after 20 weeks of gestational age. For all pregnant women, surface antigens of red blood cells were prepared using anti-A,B antibodies and D prepared from Blood Transfusion Organization of Iran by the method of agglutinaccine metacotype group blood vessels ABO and Rh and using ABO study kit (Company, Iran) and blood drops were taken by needles. Also, women with negative Rh were excluded from the study. The inclusion criteria included being in the age range of 18-35 years and primipara, and having no previous miscarriages, diabetes, infertility, exposure to smoking, hypertension prior to pregnancy, kidney and pulmonary diseases. The women’s weight increase was in the normal range during pregnancy, too. They also had no particular mental diseases. The preeclampsia in women in the case group was confirmed and then they received doses of sulfamethazine to be treated. The data were collected through the checklist prepared by the researchers. Finally, the collected data were analyzed employing descriptive statistics and Chi-square via SPSS version 16. This study was approved by the Ethics Committee of Deputy of Research at Gonabad University of Medical Science.
Results and Discussion
The mean age of women in case and control groups were 24 and 23.6 with a standard deviation of 1.8 and 1.6, respectively. The women with blood group A showed the highest frequency of preeclampsia, and the lowest frequency of preeclampsia belonged to the women with blood group O (Table 1). The Chi-square revealed a significant relationship between the incidence of preeclampsia and blood group (Table 2).
 
 
Table 1. The frequency of the blood types in women with and without preeclampsia

 
Table 2. The relationship between O blood type and non O blood types

 

The results showed that the women with blood types other than O are more susceptible to preeclampsia (hypertension and proteinuria), a finding which is in line with that of the study conducted by Lee et al. [7]. The relationship between blood type B and preeclampsia was observed in our study. Franchini et al. noted a significant relation between blood group and thrombosis risk so that von Willebrand factor (VWF) in people with blood groups other than O (A, B, AB) was higher as much as 25 percent than blood type O. That is, the people with blood types other than O bear as much as 2.2 the risk of thrombosis than the people with blood type O, a risk which can increase as much as 7 times if complicated with other acquired and inherited risk factors. There is a higher risk of thrombotic events in non-O blood group compared with O blood group because the activity of ADAMS13 enzymes in non-O phenotype, which is von Willebrand enzyme, was less in comparison to blood type O, resulting in less destruction of VWF, hence, the thrombosis risk will increase as much as four or five times [8]. Furthermore, the hemostasis proceeds towards thrombosis or an increase in coagulation during pregnancy and a decrease in the usual body inhibitors like anti-thrombin III and S protein [9].
When coagulation cascades are aggravated in pregnancy, pregnant women with this blood type are more susceptible to clotting inside the vessels, and finally the pathologic reactions inside the vessels are aggravated because blood types and consequently preeclampsia increase [10-11]. In our study, blood groups A and B enjoyed the highest frequency of preeclampsia. Blood groups A and B secrete antitumor factors which can damage the veins. Moreover, A and B blood groups stimulate the coagulation process if compared with the blood group O although there has been found a relation between blood group O and infertility [12].
Conclusions
It seems that blood groups play an effective role in increasing the hypercoagulability of hemostasis system especially in pregnancy. In other words, blood types play a significant role in inducing thrombotic complications such as preeclampsia.
Conflict of Interest
Authors have no conflict of interest.
Acknowledgments
he authors would like to thank the women participating in the study especially those with preeclampsia and thank the Clinical Development Research Center of Allameh Behlol Hospital in Gonabad University of Medical Sciences for its advice.
 
 
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