Placenta Accreta

Abstract

Objective. Placenta accreta is a life-threatening problem that is rising in incidence in the developed world. The increased risk of placenta accreta in women with placenta previa and 1 or more prior cesarean deliveries is well established and prompts careful sonographic evaluation. Our objective was to emphasize that accreta is also identified at sites other than cesarean scars. Methods. Two cases of placenta accreta without placenta previa seen in association with uterine scarring from myomectomy and uterine fibroids are described. Results. The sonographic and magnetic resonance imaging findings of accreta are reviewed in the classic setting of prior cesarean deliveries as well as myomectomy and uterine fibroids. Conclusions. We suggest that when the placenta overlies any uterine abnormality, a careful search for invasive placentation is warranted. Key words: accreta; sonography, fibroids; sonography, placenta. Maternal-Fetal Medicine, University of Ottawa, Ottawa Hospital, Ottawa, Ontario, Canada (A.A.) lacenta accreta occurs when there is a defect in the decidua basalis, allowing the anchoring villi to adhere to the myometrium. The frequency of abnormal placentation has increased 10-fold over the last 20 years and is now observed in 9.3% of women with placenta previa or in 1 per 533 deliveries. Received June 5, 2008, from the Department of1 Cesarean delivery is probably the most common cause of decidual defects, and the increase in placenta accreta may be attributed primarily to the rising cesarean delivery rate, which has risen to greater than 30% in the United States at the time of writing. Among those with previous cesarean deliveries who have placenta previa or a lowlying anterior placenta, the risk of placenta accreta increases from 24% for a single cesarean delivery to 67% for 4 cesarean deliveries.2 Other risk factors for accreta include subserosal uterine myomas, previous myomectomy, Asherman syndrome, maternal age older than 35 years, smoking, and elevated α-fetoprotein levels. 3,4 Massive hemorrhage at the time of delivery is the most important clinical issue in cases of placenta accreta.

Incidence and Risk Factors for Placenta Accreta/Increta/Percreta in the UK: A National Case-Control Study

“…Placenta praevia [3], [4], [13], [16], previous caesarean delivery [3], [4], [13], [17], [18], other previous uterine surgery [13], [19], [20], multiparity [13], [20], advanced maternal age [3], [4], [13], [16], hypertensive disorders [17], smoking [17], IVF pregnancy [21] and a female fetus [22] are all factors that have previously been suggested as being associated with a higher risk of placenta accreta/increta/percreta. Our study investigated each of these factors and found that the risk of placenta accreta/increta/percreta was independently increased in women with a previous caesarean delivery; in women with other previous uterine surgery; in women with an IVF pregnancy and in women with placenta praevia diagnosed antepartum.…”

Does hysteroscopic metroplasty for septate uterus represent a risk factor for adverse outcome during pregnancy and labor?

“…No differences in the rate of breech presentation between the groups have been found in the present study. Placenta accreta has been reported to be a possible complication of uterine surgery such as hysteroscopic myomectomy and lysis of intra uterine synechiae [ 26 ]. No study in the literature reports any case of placenta accreta or increta after metroplasty, and no case has been observed in the present study.…”

The Impact of the Time Interval Between Cycles on Pregnancy Outcome of Intrauterine Insemination

“…Nevertheless, the conclusions of relevant studies show that this concern is unnecessary [28,29] . One endometrial regeneration cycle should be su cient to allow embryo implantation [30] .…”