Abstract： Objective To investigate rational management for pregnant women with intermediate risk of Down syndrome (DS) through a retrospective analysis of second trimester maternal screening results for DS.Methods Second-trimester triple maternal serum screening for DS was performed.High risk ( ≥ 1/270) pregnant women received prenatal diagnosis.Intermediate (1/1000 to 1/270) and low (＜1/1000) risk pregnant women received routine obstetric examination.Data of ultrasound diagnosis,karyotype analysis of amniotic fluid and postpartum follow-up were collected.Outcomes of pregnant women were retrospectively analyzed.The incidences of DS among three groups were compared.Data of different groups were compared with Fisher exact or Chi-square test.Results Eighty-six thousand eight hundred and seventy-four pregnant women accepted maternal serum screening and outcomes of 86 126 cases were followed up,among which 4342 cases were DS high risk,8196 intermediate and 73 588 low risk.The incidence of DS was 6.22‰(27/4342) for high risk,0.73 ‰ (6/8196) for intermediate risk and 0.04 ‰ (3/73 588) for low risk group.The incidence of DS was higher in high risk group than in intermediate risk group (Fisher exact probability,P=0.000),and was higher in intermediate risk group than in low risk group (Fisher exact probability,P=0.000).Comparison among the three subgroups within intermediate risk group showed no significant differences (x2 =0.047,P =0.977).Conclusions Pregnant women with intermediate risk of DS should be paid more attention.Reasonable management such as ultrasound diagnosis and prenatal consultation should be provided.