Abstract： Objective To discuss the clinical features,management,pregnancy outcome and prognosis of obstetric mirror syndrome.Methods The clinical data of 12 cases with obstetric mirror syndrome at Shenzhen Maternity and Child Healthcare Hospital from April 2008 to December 2010 were collected to retrospectively analyze the clinical features, management,pregnancy outcome and prognosis.Results ( 1 ) Etiology:12 cases with obstetric mirror syndrome included 9 cases of Bart's hydrops fetalis,2 cases with fetal complicated congenital cardiac anomalies,and 1 case of unknown etiology.(2)Gestational age at diagnosis and at delivery:gestational age at diagnosis ranged from 28 to 36 weeks [ mean (31.5 ±4.7) weeks],and gestational age at delivery ranged from 28+3 to 38 weeks [ mean (32.9 ±2.9)weeks].There were no significant differences between the gestational age at diagnosis and at delivery in consistented with severe preeclampsia group and mild preeclampsia group [ (31.8 ± 2.3 ) weeks vs.(30.9 ± 7.2) weeks,(32.5 ± 2.3 ) weeks vs.(33.5 ± 3.9 ) weeks,P ＞ 0.05 ].( 3 ) The patients with obstetric mirror syndrome can present a preeclampsia-like syndrome:maternal extremity edema in 12 cases,headache and visual disturbance in 1 case,proteinuria in 11 cases,elevated blood pressure in 5 cases,elevated uric acid in 9 cases,hypoproteinemia in 12 cases,elevated creatinine in 3 case,elevated liver enzyme in 1 case,thrombocytopenia in 2 cases.The major complications included 1 case of HELLP syndrome,acute pulmonary edema,placental abruption,amnionic fluid embolism,DIC respectively,3 cases of acute kidney failure and 6 cases of postpartum hemorrhage.(4) Sonographic findings:① Hydrops fetalis:fetal ultrasound revealed pleural fluid,fetal ascites,skin edema,scalp edema,encephalocolele enlargement, hydropericardium and increased cardio-chest ratio.②Placenta megaly:the placental pathological examination revealed edematous and large in 12 cases.Placental thickness was beyond 4 cm in all cases [ (6.3 ± 1.9) cm ].③Hydramnios:hydramnios could be found in 11 cases [ amniotic fluid index ( 19.7 ± 3.1 ) cm ]. (5) Postnatal conditions:all blood pressure and laboratory findings including urine protein normalized within 5 to 7 days after delivery. (6) Pregnancy outcome:all 12 patients survived,however the perinatal mortality rate was 100％.Two of 12 cases with mirror syndrome underwent cesarean section,and 10 were vaginal delivery,of which 1 need uterine artery embolisom due to postpartum hemorrhage.Conclusions Obstetric mirror syndrome seems to simulate preeclampsia although there are distinguishing features,such as hemodilution,placental edema,and polyhydramnios.When the specific cause of obstetric mirror syndrome can not be identified and corrected,the decision for delivery should be made as soon as possibly.