Under the influence of medical ethics and other factors， the safety of medication in pregnancy has not been fully studied so far. Insomnia is a common condition during pregnancy. It may be a normal physiological manifestation after pregnancy， an early symptom of mental illness， or an inducement to relapse of mental illness. However， most of the current safety studies on the use of sedative hypnotics during pregnancy are small sample retrospective studies， and the results are inconsistent. Therefore， its safety needs to be further confirmed. This paper reviews the existing researches on the safety of sedative hypnotics in pregnancy.