Abstract： Objective To investigate the perinatal outcomes of pregnancies complicated with varying degrees of thrombocytopenia.Methods Clinical data of 305 pregnant women with thrombocytopenia,who admitted to Peking University People's Hospital from January 1,2000 to January 31,2010 were retrospectively analyzed.The etiological diagnosis of them were gestational thrombocytopenia (GT),idiopathic thrombocytopenic purpura (ITP) or undetermined.The patients were divided into 4 groups according to the minimal level of platelets in pregnancy ( platelets count was lower than 100 ×109/L at least twice) : groupⅠ,(50-100) ×109/L (n=101) ; group Ⅱ,(30-50) × 109/L (n = 85); group Ⅲ,(10-30) × 109/L (n = 87); group Ⅳ,< 10 × 109/L (n = 32).Demographic data such as pregnancy complications,treatment,neonates and follow-up results of the patients in each group were compared with ANOVA,Spearman rank correlation analysis,Chirsquare test and Chi-square trend test in SPSS 17.0.Results Medical complications in pregnancy of these patients included hypertensive disorder complicating (n = 35,11.48%) and abnormal glucose metabolism (n=23,7.54%),no difference was found in the incidence of these diseases among the four groups.There were 68 patients complicated with anemia (22.30%),40 preterm delivery (13.11%),60 postpartum hemorrhage (19.67%); there were significant differences in the incidence among the four groups (P＜0.05),the incidence increased with the aggravation of thrombocytopenia (P＜0.05).There were 2 cases of puerperal infection (0.66%),no maternal deaths.Fifty-one patients (16.72%) accepted treatment of corticosteroids or Gamma globulin during pregnancy.There were 116 cases (38.03%) of vaginal delivery and 189 cases (61.97%) of cesarean section.The postpartum bleeding amount within 24 hours increased with the aggravation of thrombocytopenia.Two hundred and eleven (69.18%) patients were followed up and platelet count regained normal,among which 152 cases recovered within six months after delivery.The recovery rates were 90.59% (77/85),82.36% (42/51),46.16% (24/52) and 39.13% (9/23) from group Ⅰ to group Ⅳ,as declined with the aggravation of thrombocytopenia in pregnancy ( x2trend = 42.616,Ptrend =0.000).Among the 306 perinatal fetuses,neonatal outcomes included 301 live births,5 fetal deaths,4 early neonatal deaths,4 low birth-weight infants after term birth,1 intracranial hemorrhage and 18 (5.98%) neonatal thrombocytopenia cases.Incidence of neonatal thrombocytopenia increased with the aggravation of maternal thrombocytopenia.Sixteen cases of neonatal thrombocytopenia recovered at 3-8 weeks after birth,but two cases did not recover within three years during followed up.Conclusions The perinatal outcomes are different in pregnancies complicated with varying degrees of thrombocytopenia.As thrombocytopenia in pregnancy become worse,the risk of anemia,premature delivery,postpartum hemorrhage and neonatal thrombocytopenia increases.While,perinatal outcomes may be better under close perinatal care.