WASHINGTON -- Characteristic findings on transabdominal ultrasound and color mapping help predict placenta accreta, Thomas C. Woodring, M.D., said at the annual meeting of the Central Association of Obstetricians and Gynecologists.
Diagnosing the condition before delivery allows the patient and the delivery team to prepare for the likelihood of severe hemorrhage necessitating curettage, hypogastric vessel ligation, or hysterectomy, said Dr. Woodring of the University of Mississippi Medical Center, Jackson.
Although the precise etiology of the condition is unknown, placenta accreta can occur after "any process or procedure capable of scarring the endometrial cavity," predisposing to anomalous myometrial invasion by the placental villi. These include grand multiparity; Asherman's syndrome; and previous cesarean delivery, uterine curettage, myomectomy, or uterine reconstructive surgery. "Particularly disturbing is the nearly 40% rate of accreta in women with two or more cesarean deliveries and a central previa," Dr. Woodring noted.
He and his associates reviewed 5 years of ultrasound reports from their hospital in cases where placenta accreta was suspected prenatally. There were 12 such cases out of 31,083 ultrasound studies.
Three sonographic signs were found to predict placenta accreta: concomitant placenta previa; large or numerous placental venous "lakes"; and a remarkably thin, or even nonvisualized, lower uterine segment.
Two Doppler color flow signs that also predicted placenta accreta were areas of turbulent or complicated blood flow at the uteroplacental interface, and irregular blood flow underlying the maternal urinary bladder, he said in a poster presentation.
All 12 patients had histories of at least one prior cesarean delivery, with a median of two. Seven women (58%) had at least one episode of third-trimester vaginal bleeding. A concomitant placenta previa was detected before delivery in 11 (92%).
Placenta accreta was confirmed at delivery in 10 of the 12 cases, and the remaining 2 cases were considered false positives. All 10 women (83% of the total study group) required hysterectomy to control bleeding. Nine women (75%) required transfusions, with a median of 4 units required (range, 2-17 units).
Neonatal outcomes were uniformly good, with a median birth weight of 2,517 g and a median 5-minute Apgar score of 9. There were no further maternal complications.
Sonographic studies that aid early diagnosis of placenta accreta may well reduce peripartum morbidity and mortality by preparing the patient and physician for the expected operative challenges, he said.
BY MARY ANN MOON
COPYRIGHT 2004 International Medical News Group
COPYRIGHT 2004 Gale Group