Objective:To determine whether matal β-human chorionic gonadotropin(β-Hcg)level in second-trimester may be associated with subsequent development of pregnancy-induced hypertension(PIH).Methods: Seven hundred and sixty-two women in mid-trimester were to have matal urine β-Hcg standardized concentrations and matal serum β-Hcg measurements.Their case histories were recorded and reviewed from mid-trimester to delivery.The relation was observed between matal urine,serum markers and subsequent development of PIH.Results: Among 762 women,504 cases were normal pregnancies,42 cases had PIH,94 cases had premature rupture of membrane(PROM),69 cases had preterm delivery(PD),53 other cases were excluded by various reasons.The levels of matal urine,serum β-Hcg in PIH were(61.75±9.78)IU/L and(304.56±54.17)ng/mg respectively,which were higher significantly than normal pregnancy group([20.65±7.61]IU/L and[146.34±47.81]ng/mg,P<0.05).When matal serum,urine β-Hcg levels ≥2 MOM(multiple of mean),the incidences of developing PIH were increased significantly as compared with those of β-Hcg <2 MOM women.The incidence of PIH increased from 5.1% in pregnancies with urine β-Hcg ≥2 MOM to 11.7% in cases with urine β-Hcg ≥4 MOM.Conclusion: The elevation of matal mid-trimester urine,serum β-Hcg levels is not only an early signal for dysfunction of placenta but also a dangerous signal for development of PIH.Second-trimester matal urine β-Hcg measurement proves to be superior to serum marker in clinical prediction.