RT Book, Section A1 Kowalczyk, John J. A2 Hess, Philip E. A2 Li, Yunping A2 Kowalczyk, John J. A2 Stiles, Justin K. SR Print(0) ID 1199673614 T1 Nonobstetric Surgery During Pregnancy T2 Obstetric Anesthesia: Quick References & Practical Guides YR 2023 FD 2023 PB McGraw Hill PP New York, NY SN 9781264671465 LK obgyn.mhmedical.com/content.aspx?aid=1199673614 RD 2024/12/11 AB Nonobstetric surgery during pregnancy is common and occurs in between 0.3% and 2.2% of pregnancies. Retrospective human studies have not conclusively shown that any anesthetic agent results in increased congenital abnormalities. The conclusions of past studies have suggested possible teratogenic effects associated with nitrous oxide and benzodiazepines. However, more recent large retrospective studies have not supported these findings. General timing principles include1: