Diagnostic Ultrasound - Abdomen and Pelvis

Retained Products of Conception
Diagnoses: Female Pelvis
• Delayed involution of superficial modified spiral arteries at
placental attachment site
○ Leads to delayed postpartum hemorrhage
• Diagnosed during pathological analysis of D&C or
hysterectomy specimens of placenta after excluding
presence of chorionic villi, endometritis, and gestational
trophoblastic disease
• Etiology remains poorly understood
Enhanced Myometrial Vascularity
• Presence of marked vascularity over full thickness of
myometrium related to involution of placental bed after
pregnancy and miscarriage
○ Myometrial hypervascularity represents involuting peritrophoblastic
flow
• Occur in 50% of normal postpartum patients at day 3
• Also known as uterine non-AVM
• Disappears spontaneously
Submucosal Leiomyoma
• Submucosal mass protruding into endometrium with
increased vascularity
• May be contiguous with underlying myometrium
Endometrial Polyp
• Intraluminal pedunculated endometrial mass
• Typically ovoid and echogenic
• Single vascular pedicle
PATHOLOGY
General Features
• Presence of chorionic villi indicates persistence of placental
tissue
Staging, Grading, & Classification
• Grading for degree of endometrial vascularity of RPOC with
respect to myometrium
○ Type 0: Avascular
○ Type 1: Minimal vascularity
– Vascularity < myometrium
○ Type 2: Moderate vascularity
– Vascularity = myometrium
○ Type 3: Marked vascularity
– Vascularity > myometrium
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Postpartum hemorrhage
– RPOC may present as primary or secondary PPH
□ Primary PPH (within 1st 24 hours)
□ Secondary PPH (24 hours to 6 months post partum)
– May rarely present weeks after delivery or termination
with vaginal bleeding or infection
○ Pain
○ Fever
Demographics
• Epidemiology
○ ~ 1% of all pregnancies
○ More frequent following termination and 2nd trimester
deliveries
○ ↑ incidence with
– Placenta accreta
– Instrumentation during delivery
– Failure to progress during delivery
Treatment
• Options, risks, complications
○ May monitor 24-48 hours, especially if ultrasound
findings are equivocal
– May repeat ultrasound to reevaluate
– Correlation with human chorionic gonadotropin (hCG)
levels may be helpful to distinguish RPOC from
invasive molar pregnancy
○ Expectant management
– RPOC may pass spontaneously or with uterotonic
medications
○ D&C
– Performed in cases of persistent bleeding or obvious
RPOC
– Failure to evacuate may lead to prolonged
hemorrhage and infection
○ Uterine artery embolization
– Treatment of choice for excessive bleeding
– May be diagnostic as well as therapeutic for both
RPOC and AVM
○ Hysteroscopy
– Directed visualization of intrauterine cavity may be
necessary in cases of incomplete D&C
DIAGNOSTIC CHECKLIST
Image Interpretation Pearls
• Uterine atony vs. RPOC: Primary differential for immediate
postpartum hemorrhage
○ Atony: Normal-appearing cavity
○ RPOC: Thickened endometrial echo complex or
echogenic, intracavitary mass
• If endometrial thickness < 10 mm and without internal
vascularity, RPOC unlikely
SELECTED REFERENCES
1. Goyal S et al: Acquired uterine arteriovenous malformation developing in
retained products of conception: a diagnostic dilemma. J Obstet Gynaecol
Res. 40(1):271-4, 2014
2. Zubor P et al: Recurrent secondary postpartum hemorrhages due to
placental site vessel subinvolution and local uterine tissue coagulopathy.
BMC Pregnancy Childbirth. 14:80, 2014
3. Sellmyer MA et al: Physiologic, histologic, and imaging features of retained
products of conception. Radiographics. 33(3):781-96, 2013
4. Atri M et al: Best predictors of grayscale ultrasound combined with color
Doppler in the diagnosis of retained products of conception. J Clin
Ultrasound. 39(3):122-7, 2011
5. Kitahara T et al: Management of retained products of conception with
marked vascularity. J Obstet Gynaecol Res. 37(5):458-64, 2011
6. Kamaya A et al: Retained products of conception: spectrum of color Doppler
findings. J Ultrasound Med. 28(8):1031-41, 2009
7. Weydert JA et al: Subinvolution of the placental site as an anatomic cause of
postpartum uterine bleeding: a review. Arch Pathol Lab Med. 130(10):1538-
42, 2006
8. Durfee SM et al: The Sonographic and Color Doppler Features of Retained
Products of Conception. J Ultrasound Med. 24(9):1181-1186, 2005
9. Sadan O et al: Role of sonography in the diagnosis of retained products of
conception. J Ultrasound Med. 23(3):371-4, 2004
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