Sex/Gender Differences in Postoperative Nausea and Vomiting

Previous guidelines have identified independent risk factors for postoperative nausea and vomiting (PONV) that showed statistical significance in multivariable analyses of large cohort studies. Patient-specific risk factors include female sex, a history of PONV and/or motion sickness, nonsmoking status, and young age. A Korean study found that female sex was the most influential risk factor for PONV. A sex/gender difference was not noted in preadolescence or beyond the eighth decade of life; however, the cause of sex/gender differences in PONV has yet to be determined because other studies have claimed that female hormones are unrelated to PONV. Recent studies have explored polymorphisms of the 5-hydroxytryptamine receptor type 3B gene, female-specific effects of the 5-hydroxytryptamine receptor 3A gene, 5-hydroxytryptamine 3B gene polymorphisms, and TACR1 gene polymorphisms, aiming to identify the causes of sex/gender differences in PONV. The paradigm of postoperative care must also change due to the recent increase in outpatient, noninvasive laparoscopic surgery, enhanced recovery after surgery (ERAS) protocols, and patients’ increasing demand for these procedures. The prevention and management of PONV are important for increasing patient satisfaction. Understanding PONV risk factors improves risk assessment and helps to reduce the perioperative risks. Since research on sex/gender differences should be conducted on genes other than those encoding serotonin, neurokinin, and dopamine receptors, and considering that female sex is the most important factor associated with high-risk patients, it is time for active research on sex/gender to enable the establishment of comprehensive evidence-based guidelines.