Journal of Ultrasound in Medicine, Vol 10, Issue 8 451-456, Copyright © 1991 by American Institute of Ultrasound in Medicine
Ultrasound of the postpartum uterus. Prediction of retained placental tissue
B. S. Hertzberg and J. D. Bowie
Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710.
We reviewed ultrasound images an 53 postpartum patients referred for
possible retained products of conception and correlated specific ultrasound
patterns with clinical and pathologic follow-up. The most common finding in
patients with retained placental tissue was an echogenic mass in the
uterine cavity, seen in 9 of 11 patients with pathologically proven
retained placental tissue. In the remaining 2 patients with pathologically
confirmed retained placenta, a heterogeneous mass was seen in the uterine
cavity at some point during the course of serial sonography. Retained
placental tissue was unlikely when ultrasound demonstrated a normal uterine
stripe (n = 18), endometrial fluid (n = 6), or hyperechoic foci in the
uterine cavity without an associated mass (n = 17). The latter finding was
often associated with recent uterine instrumentation. The sonographic
appearance of retained placental tissue is variable, but detection of an
echogenic mass in the uterus strongly supports the diagnosis. A
heterogeneous mass is sometimes caused by retained placenta, but can also
be secondary to blood clots or infected or necrotic material in the absence
of placental tissue. Sonographic evaluation for retained products of
conception is best done before uterine instrumentation to avoid confusion
with iatrogenically introduced air.
