US Pelvis Transvaginal Pelvic US using a combined transvaginal and transabdominal approach is the primary modality of choice for the investigation of late PPH as RPOC with or without endometritis is one of the major causes of secondary or late PPH. Although detection of an echogenic or mixed-echo pattern endometrial mass has the highest sensitivity for the detection of RPOC, this is a nonspecific finding that overlaps with the normal postpartum appearance [14,31]. The most specific finding is a vascular echogenic mass, although flow may not be identified in all RPOC. Another US finding in RPOC is a thickened endometrial echo complex with a variable cutoff of 8 to 13 mm [25,32]. US can be used in this setting to assess for coexisting pathology and complications, such as RPOC, hematoma, or abscess. US can detect most pelvic hematomas [13], including bladder flap hematomas [14,15] with superimposed echogenic foci of air suggesting infection [15]. Although uterine scar dehiscence may be seen on US as an irregular thinned uterine wall or a myometrial defect [14], differentiation from the normal appearance of the cesarean section scar can be difficult. VUA, including uterine artery pseudoaneurysms, are a relatively rare cause of PPH [19,20] and most commonly arise from the uterine artery. VUA appear as hypoechoic tortuous channels or masses in the myometrium with turbulent flow on color Doppler and high-velocity and low-resistance flow on spectral analysis. It can be difficult to distinguish acquired VUA from subinvolution of the placental bed [19,26] or to assess its severity or need for intervention on US [19]. A dilated vessel in the myometrium may suggest the diagnosis of pseudoaneurysm. Postpartum Hemorrhage Variant 4: Postpartum hemorrhage. Late (greater than 24 hours to 6 weeks) after vaginal delivery. Initial imaging. Secondary or late PPH is typically defined as any significant uterine hemorrhage occurring between 24 hours to 6 weeks postpartum.
Postpartum Hemorrhage. US Pelvis Transvaginal Pelvic US using a combined transvaginal and transabdominal approach is the primary modality of choice for the investigation of late PPH as RPOC with or without endometritis is one of the major causes of secondary or late PPH. Although detection of an echogenic or mixed-echo pattern endometrial mass has the highest sensitivity for the detection of RPOC, this is a nonspecific finding that overlaps with the normal postpartum appearance [14,31]. The most specific finding is a vascular echogenic mass, although flow may not be identified in all RPOC. Another US finding in RPOC is a thickened endometrial echo complex with a variable cutoff of 8 to 13 mm [25,32]. US can be used in this setting to assess for coexisting pathology and complications, such as RPOC, hematoma, or abscess. US can detect most pelvic hematomas [13], including bladder flap hematomas [14,15] with superimposed echogenic foci of air suggesting infection [15]. Although uterine scar dehiscence may be seen on US as an irregular thinned uterine wall or a myometrial defect [14], differentiation from the normal appearance of the cesarean section scar can be difficult. VUA, including uterine artery pseudoaneurysms, are a relatively rare cause of PPH [19,20] and most commonly arise from the uterine artery. VUA appear as hypoechoic tortuous channels or masses in the myometrium with turbulent flow on color Doppler and high-velocity and low-resistance flow on spectral analysis. It can be difficult to distinguish acquired VUA from subinvolution of the placental bed [19,26] or to assess its severity or need for intervention on US [19]. A dilated vessel in the myometrium may suggest the diagnosis of pseudoaneurysm. Postpartum Hemorrhage Variant 4: Postpartum hemorrhage. Late (greater than 24 hours to 6 weeks) after vaginal delivery. Initial imaging. Secondary or late PPH is typically defined as any significant uterine hemorrhage occurring between 24 hours to 6 weeks postpartum.