Objective To investigate the uterine cavity sonogram of irregular vaginal bleeding over 15 days after medical abortion by transvaginal sonography.Methods From July to November 2003,in Zhongda Hospital of Southeast University,a study of uterine cavity sonogram was performed in 20 normal pregnancies with irregular vaginal bleeding over 15 days after medical abortion.Transvaginal color Doppler energy and pulsed-wave Doppler technique were used as routine sonography scanning modalities.The hemodynamic parameters of uterine spiral arteries(SA),including peak systolic velocity(PSV),end diastolic velocity(EDV),resistance index(RI),pulsation index(PI),and systolic/diastolic velocity ratio(S/D),were measured before and after abortion.On day 15,all subjects were performed D & C and the results were compared to those of pathology.Results For 3 women,no retained tissue and no spiral arteries signals were detected.For 17 women,retained tissue and spiral arteries signals were detectable.2 cases were confirmed as complete abortion by surgery and pathology,18 cases were confirmed as incomplete abortion by surgery and pathology.Conclusions Basal deciduas retained may be the most important factor effecting the abortion.