Investigation of Beta-2 Adrenergic Receptor Gene Polymorphisms and Their Association with Maternal Hypotension During Cesarean Under Spinal Anesthesia in a Turkish Population

Objective: Maternal hypotension is a common complication of spinal anesthesia for cesarean delivery, pose a risk to both mother and fetus. Prophylactic and therapeutic strategies must ensure hemodynamic stability. This prospective study examined whether single-nucleotide polymorphisms (SNPs) in codons 16 (Arg16Gly) and 27 (Gln27Glu) of the Beta-2 adrenergic receptor (β2AR) gene affect the incidence of hypotension and ephedrine requirements in Turkish women undergoing elective cesarean section under spinal anesthesia.
Methods: Five hundred and twenty term pregnant women scheduled for elective cesarean delivery were enrolled. Preoperative, all patients received 500 mL lactated Ringer’s solution. Hemodynamic parameters (mean arterial pressure [MAP] and heart rate [HR] were recorded at baseline and at 5, 10, 20, 40, and 60 minutes. Ephedrine dosing followed a standardized systolic blood pressure (SBP) based protocol.
Results: Genotype distribution was 270 homozygous variants (51.9%), 230 heterozygotes (44.2%), and 20 wild types (3.9%). Hypotension occurred in 330 patients (64.7%), all treated with ephedrine. No significant differences emerged among genotypes in MAP, HR, frequency of hypotension, or total ephedrine dose (respectively P=.061, P=.054). Although homozygous mutants trended toward slightly higher cumulative ephedrine usage and wild types toward lower usage, these differences were not statistically significant. Neonatal Apgar scores at 1 and 5 minutes remained within normal limits across all groups.
Conclusion: β2AR Arg16Gly and Gln27Glu polymorphisms do not appear to influence the risk of spinal anesthesia–induced hypotension or ephedrine requirements in this cohort of Turkish parturients. These findings lay the groundwork for larger, multicenter studies spanning diverse ethnic populations.