Background: To explore the role of oxytoc in receptor gene (OXTR gene) polymorphism and plasma oxytocin levels in predicting the incidence of chronic persistent post-surgical pain (CPSP) following caesarean delivery (CD).

Methods: This observational follow-up study was conducted following IEC-H approval, prospective CTRI registration and written informed consent from each participant.We included obstetric patients of ASA grade II or III undergoing CD under either SAB or GA and excluded if had chronic pain, neurological disorders or cognitive dysfunction. A base line venous blood sample for plasma oxytoc in levels and OXTR genepolymorphism study was withdrawn and conducted as per the standard protocol. The pain severity and neuropathic component were assessed at 6, 10 and 14th week, postoperatively. Statistical tests like unpaired student-test, Fisher-exact test, correlation tests and binary logistic regression were used.

Results: A total of 50 patients were included and24% (n=12) of them had CPSP. The risk score of alleles with respect to CPSP shows that T allele has OR of 0.43 (95%CI= 0.08-2.2, P value-0.3) and C allele has OR of 1.06 (95% CI=0.11-11.2, P-value 0.96).

A significant correlation between mean oxytocin levels and NRS at 6th (R-0.34, p-value: 0.015) and 10th week (R-0.26, p-value: 0.067) was observed; however, not at 14th week. The mean oxytocin level is significantly raised in patients undergoing emergency CD vs elective CD i.e. 2.22 ± 1.17 vs 1.02 ± 1.00; p-value=0.013. Amongst patients undergoing emergency CD, a significant negative correlation between oxytocin levels and NRS-R atall time points i.e.6th, 10th and 14th weeks and NRS-M at 6th week only were observed

Conclusion: We observed the protective effect of T allele of OXTR rs53576 and the antinociceptive effect of endogenous oxytocinin the pathogenesis of CPSP following CD.