Association between COMT polymorphism, labor anxiety, and analgesia in pregnant women

Xiaohui Ren,1,2 Le Zhang,3 Qiuxia Xiao,2 Daxue Huang,1 Qing Liu,2 Ying Zhang2 1Department of Anesthesiology, Neijiang City Central Maternal and Child Health Care Hospital, Neijiang 641000, Sichuan, China; 2Department of Anesthesiology and Pain Management, Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou 646000, Sichuan, China; 3Department of Anesthesiology, Sichuan Provincial Armed Police Corps Hospital, Leshan 614000, Sichuan, China Background: COMT gene polymorphism is associated with mental disorders and sensitivity to pain. In this study, we investigated the association between the COMT gene polymorphism and labor anxiety and analgesia in pregnant women.Subjects and methods: A total of 425 pregnant women undergoing labor analgesia were selected from May 2016 to February 2018. The COMT gene polymorphism was detected through the PCR with restriction fragment length polymorphism technique before childbirth. According to a COMT genotype, the enrolled pregnant women were subdivided into the Val/Val (allele GG) group, the Met/Met (allele AA) group, and the Val/Met (allele GA) group. Then, the intervertebral space of all pregnant women was injected with 3 mL of 2% lidocaine +6 mL of 0.08% ropivacaine and 6 µg of fentanyl. Labor analgesia was administered as follows: 80 mg of 0.08% ropivacaine +100 µg of fentanyl + normal saline to 100 mL. The general characteristics of the women were examined and recorded. In addition, the State Anxiety Inventory (SAI), VAS, Ramsay sedation score, and epinephrine and norepinephrine levels were compared and analyzed.Results: A total of 391 pregnant women were enrolled in this study; among these pregnant women, there were 180 pregnant women in the GG group, 132 in the GA group, and 99 in the AA group. The minor allele frequency of COMT polymorphism among these pregnant women was 32.8%. Compared with the GG group, the SAI and VAS scores were higher, the Ramsay sedation score was lower, and the epinephrine and norepinephrine levels were higher in AA and GA groups (P0.05).Conclusion: The COMT gene polymorphism was associated with labor anxiety and analgesia among pregnant women, and the Val158Met mutation in the COMT gene could lead to worse labor anxiety and less-effective labor analgesia in pregnant women. Keywords: COMT, polymorphism, labor anxiety, labor analgesia