Association between Serum HLA-G Levels in The First Trimester of Pregnancy and The Onset of Preeclampsia: A Systematic Review and Meta-analysis Study

Document Type : Systematic Review


1 Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran

2 Department of Radiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran

3 Department of Radiology, Isfahan University of Medical Sciences, Isfahan, Iran

4 Department of Gynecology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences (AJUMS), Ahvaz, Iran

5 Islamic Azad University Tehran Medical Branch, Tehran, Iran

6 Department of Cardiology, Faculty of Medicine, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran

7 Non-Communicable Diseases Research Center, Ilam University of Medical Sciences, Ilam, Iran


Human leukocyte antigen G (HLA-G) levels are among the biomarkers suggested for pre-eclampsia (PE). This study
is aimed at determining the possible relationship between low soluble HLA-G (sHLA-G) levels in maternal blood at
the beginning of pregnancy and subsequent PE. We searched the international scientific databases of Web of Science,
Embase, PubMed, Cochrane, and Scopus. We extracted the studies investigating the relationship between the serum
levels of HLA-G in the first trimester of pregnancy and the onset of PE using the appropriate keywords. The collected
data were analyzed using the random-effects meta-analysis model and STATA (version 14). A total of 5 studies met
the eligibility criteria, and the total sample size was 668 subjects. The mean and SD age of case subjects was 31.41 ±
4.16 years, while it was 30.56 ± 3.5 for control subjects. According to the findings, there was an inverse relationship
between HLA-G serum level in the first trimester of pregnancy and the subsequent onset of PE, standard mean difference
(SMD)=-1.51 [95% confidence interval (CI): -2.26, -0.75, I2=90.8%, P=0.000]. Based on these results, low
sHLA-G level in early pregnancy has a positive correlation with subsequent PE, and the significant role of sHLA-G
in the early stages of placentation can be proven.


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