Gravid status is not associated with postoperative nausea and vomiting: a matched case-control study

Postoperative nausea and vomiting (PONV) is a common and unpleasant complication of general anesthesia. There are well-known risk factors that predispose a patient to develop PONV. While studies exist that explore PONV incidence in gravid and non-gravid women separately, limited studies exist to compare the two cohorts to identify if pregnancy is associated with increased risk for PONV or differences in PONV prophylaxis and treatment.

This is a retrospective case-control cohort study, with 1:2 matching based on age, year of surgery, and surgical procedure. Electronic medical records were abstracted for demographic information, predisposing risk factors, prophylactic antiemetics, PONV documentation, rescue antiemetics, PACU stay, and length of hospitalization. Analyses of risk factors for PONV were performed using logistic and multinomial logistic regression analyses.

237 gravid women who underwent non-obstetric procedures with general anesthesia were identified and matched with 474 non-gravid women. PONV complicated the course of 51 (21.5%) gravid and 72 (15.2%) non-gravid women. The number of prophylactic antiemetics was fewer among gravid (median 2 [1, 2]) than non-gravid (3 [2, 3]) women (P < 0.001). No association was found between gravid status and risk for PONV (adjusted odds ratio 1.35 [95%CI 0.84, 2.17], P = 0.222). Gravid women had longer hospital lengths of stay (P < 0.001), despite having shorter surgical duration (P = 0.015).

The risk for PONV is similar between gravid and similarly aged women. However, anesthesiologists administer fewer prophylactic antiemetics to gravid women during non-obstetric surgery.