AIMS: This study aimed to identify the different expression of circular RNAs 
(circRNAs) in the placental tissues of pregnant women with preeclampsia (PE) and 
to provide a new avenue of research regarding the pathological mechanisms of PE.
METHODS: In this study, we collected 40 placental tissues from PE patients and 
35 placental tissues from gestational age-matched patients who gave premature 
birth. Arraystar circRNA Microarray Technology (KANGCHEN, Shanghai, China) was 
used to analyze the differential expression of circRNAs. According to the basic 
content of circRNAs in the two groups and their fold changes and due to the 
practicability of the designed divergent primers of each candidate circRNA, we 
selected three up-regulated circRNAs, hsa_circRNA_100782, hsa_circRNA_102682 and 
hsa_circRNA_104820, to validate the data. Real-time quantitative reverse 
transcriptase-polymerase chain reaction (qRT-PCR) was utilized to estimate the 
Ct values in both groups. We further evaluated the differences with a paired 
t-test and a receiver operating characteristic (ROC) curve.
RESULTS: Many circRNAs were found to be differentially expressed in PE placental 
tissues versus their controls; of these, 143 circRNAs were up-regulated and 158 
were down-regulated. The expression levels of hsa_circRNA_100782 (p < 0.05), 
hsa_circRNA_102682 (p < 0.05), and hsa_circRNA_104820 (p < 0.0001) were 
validated as significantly up-regulated in the experimental group compared with 
the controls. Finally, we performed a literature comparison to forecast the 
possible mechanisms of circRNA function during PE.
CONCLUSION: circRNA expression significantly differed in placental PE tissues 
compared with controls. According to the circRNA microarray results and the 
existing papers, circRNAs may contribute to the pathogenesis of PE by acting as 
miRNA sponges; this possibility requires additional investigation in future 
studies.