Abstract： Objective To discuss the interaction of pregnancy and myasthenia gravis(MG) and the management of pregnancy with MG.Methods Seven cases of pregnancy with MG in Peking Union Medical College Hospital were analyzed retrospectively,with respect to the therapy of MG,pregnancy complications and outcomes.Results Totally 38 683 pregnant women were admitted to Peking Union Medical College Hospital between Oct.1983 and Oct.2010.Among them there were 9 patients suffered from MG,with the incidence of 0.023％.Two pregnancies were terminated because of personal reasons,and seven continued.( 1 ) Onset of MG:in the 7 cases,6 were diagnosed before conception,with the mean course of 5.9 years.The other one occurred in the third trimester.(2) Management:all the cases were under close surveillance during pregnancy.Four women took thymectomy before conception,and one of them kept taking medication after surgery. In those who received thymectomy,3 cases remained stable and 1 case worsened during prenancy.The latter one took medication at 33 weeks,and continued to full term.MG exacerbated in the other three women who had not undergone thymectomy before conception.Among them, one woman complicated with systemic lupus erythematosus and lupus nephritis delivered the baby at 31 weeks.(3) Delivery and neonatal outcomes:cesarean deliveries were performed in 5 cases and the other two underwent vaginal deliveries.All the newborns were admitted to neonatal intensive care unit for surveillance.There were three smaller than gestational week (SGA) infants.No MG was observed in newborns.Conclusions Patients with MG should have an overall evaluation before conception.The course of MG during pregnancy is unpredictable.They may get a promising outcome under the control of a multidisciplinary team including obstetricians and neurologists.Newborns should be carefully monitored for sings of transitory MG in the department of pediatrics.