To explore the ultrasonic characteristics of massive vaginal bleeding caused by uterine arteriovenous fistula.

Ultrasound images and clinical data of 20 patients admitted to Beijing Obstetrics and Gynecology Hospital, Capital Medical University for massive vaginal bleeding from January 2015 to December 2018 were collected, analyzed, and summarized. All patients were confirmed by arteriography as having uterine arteriovenous fistula.

There were a total of 20 cases of massive vaginal bleeding caused by uterine arteriovenous fistula, including 9 after natural delivery, 4 after mid-term labor induction, 4 after induced abortion, 2 after drug abortion, and 1 after spontaneous abortion. Grayscale ultrasonography showed that all the 20 patients presented with intrauterine heterogeneous echo, ranging from 1.7 cm×1.3 cm×0.6 cm to 5.3 cm×5.8 cm×3.1 cm, of whom 8 had cystic areas with whirling echo in the intrauterine cavity, 8 showed hypoechoic changes in the lesioned myometrium, 10 showed only heteroechoic changes, and 2 showed no obvious changes in the myometrium. Color Doppler flow imaging showed that 10 patients presented with thick single-striped color blood flow, and 10 patients presented with multi-striped color blood flow. The blood flow trend was all shown as passing through the myometrium, which extended from the subserosal myometrium to the uterine cavity. Pulsed wave Doppler showed that all the 20 patients presented with the arterial blood flow spectrum with low resistance; the mean resistance index (RI) was 0.34 (0.19-0.48), mean pulse index (PI) was 0.47 (0.29-0.65), and peak systolic velocity (PSV) varied between 11.8-117.3 (mean, 54.3) cm/s.

Heterogeneous echoes are present in the uterine cavity in all patients with massive vaginal bleeding caused by uterine arteriovenous fistula. On gray scale ultrasound, the myometrium of the lesion has no specific manifestations, and the myometrium echo could be heterogeneous, anechoic, or hypoechoic, even without obvious changes. On color Doppler, it is characterized by thick single-striped or multi-striped flow throughout the myometrium extending from the subserosal myometrium to the uterine cavity. On spectrum Doppler, the resistance of arterial blood flow is low and PSV varies considerably.