The most diagnostic combination of US findings is an echogenic endometrial mass that is vascular [27]. The presence of debris and gas is relatively common in the early postpartum period, in as much as 20% to 25%. Thickened endometrial echo complex, up to 2 to 2.5 cm in diameter, is nonspecific in this early postpartum period [28]. US can be used in this setting to assess for coexisting pathology and complications, such as RPOC or hematoma. US can detect most pelvic hematomas [13], including bladder flap hematomas [14,15]. 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 pseudoaneurysm, are a relatively rare cause of early PPH, occurring particularly in the traumatic setting [19,20], and most commonly arise from the uterine artery. VUA appear as hypoechoic tortuous channels or masses in the myometrium with characteristic Doppler findings [14,19] with turbulent flow on color Doppler and high-velocity and low-resistance flow on spectral analysis and may be associated with a peripheral echogenic hematoma [20]. 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. Variant 2: Postpartum hemorrhage. Early (within first 24 hours) after vaginal delivery. Initial imaging. The most common cause of early PPH is related to uterine atony or lack of effective uterine contraction after delivery and is typically a clinical diagnosis in >75% of patients. It is initially treated by uterine massage and uterotonic drugs such as oxytocin, and the majority of patients respond well to these treatments.
Postpartum Hemorrhage. The most diagnostic combination of US findings is an echogenic endometrial mass that is vascular [27]. The presence of debris and gas is relatively common in the early postpartum period, in as much as 20% to 25%. Thickened endometrial echo complex, up to 2 to 2.5 cm in diameter, is nonspecific in this early postpartum period [28]. US can be used in this setting to assess for coexisting pathology and complications, such as RPOC or hematoma. US can detect most pelvic hematomas [13], including bladder flap hematomas [14,15]. 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 pseudoaneurysm, are a relatively rare cause of early PPH, occurring particularly in the traumatic setting [19,20], and most commonly arise from the uterine artery. VUA appear as hypoechoic tortuous channels or masses in the myometrium with characteristic Doppler findings [14,19] with turbulent flow on color Doppler and high-velocity and low-resistance flow on spectral analysis and may be associated with a peripheral echogenic hematoma [20]. 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. Variant 2: Postpartum hemorrhage. Early (within first 24 hours) after vaginal delivery. Initial imaging. The most common cause of early PPH is related to uterine atony or lack of effective uterine contraction after delivery and is typically a clinical diagnosis in >75% of patients. It is initially treated by uterine massage and uterotonic drugs such as oxytocin, and the majority of patients respond well to these treatments.