Placenta accreta: spectrum of US and MR imaging findings.
ABSTRACT Placenta accreta (PA) encompasses various types of abnormal placentation in which chorionic villi attach directly to or invade the myometrium. PA is a significant cause of maternal morbidity and mortality and is now the most common reason for emergent postpartum hysterectomy. Its prevalence has risen tenfold in the United States over the past 50 years, primarily due to the increasing percentage of pregnant patients undergoing primary and repeat cesarean sections. Placenta previa and previous cesarean section are the two most important known risk factors for PA. Accurate prenatal identification of affected pregnancies allows optimal obstetric management. Ultrasonography (US) remains the diagnostic standard, and routine US examination at 18-20 weeks gestation affords an ideal opportunity to screen for the disorder. Placental lacunae and abnormal color Doppler imaging patterns are the most helpful US markers for PA. In recent years, there has been increased interest in magnetic resonance (MR) imaging for the evaluation of PA, since it can provide information on depth of invasion and more clearly depict posterior placentas. The most reliable MR imaging findings are uterine bulging, heterogeneous placenta, and placental bands. Focal interruptions in the hypointense myometrial border may also be helpful. PA is a clinical and diagnostic challenge that is being encountered with increasing frequency. Clinicians should be aware of the clinical issues, risk factors, and imaging findings associated with PA to facilitate optimal case management.
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ABSTRACT: To review 10 years' experience of obstetric hysterectomy in a university teaching hospital. A retrospective study of all cases of caesarean or postpartum hysterectomy between 1984-1994. Demographic data and clinical details including indications for operation, nature of surgical management and complications were analysed. The incidence of obstetric hysterectomy was 1 in 1420 deliveries. Overall, 0.32% of caesarean sections and 0.02% of vaginal deliveries were complicated by emergency obstetric hysterectomy. Morbidly adherent placenta (32.7%) was the most common cause of uncontrollable haemorrhage. Prior caesarean delivery and placenta praevia were the main risk factors for its development. Operative complications included intra-operative hypotension (33.3%), urinary tract injury (22.2%) and re-exploration for persistent haemorrhage (12.5%). There was one maternal death due to suspected air embolism. Emergency obstetric hysterectomy, though uncommon, remains a potentially life-saving procedure which every obstetrician must be familiar with. It is extremely important to have early surgical intervention, prompt resuscitation and management by experienced medical staff to minimise morbidity and mortality.European Journal of Obstetrics & Gynecology and Reproductive Biology 09/1997; 74(2):133-7. · 1.84 Impact Factor
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ABSTRACT: Our purpose was to define the clinical risk factors associated with placenta previa-placenta accreta. Hospital records were reviewed of all cases of placenta accreta confirmed histologically between January 1985 and December 1994. Additionally, we reviewed the records of all women with placenta previa and all those undergoing cesarean hysterectomy during the same period. Multiple logistic regression analysis was used to identify independent clinical risk factors for placenta accreta. Among 155,670 deliveries, 62 (1/2510) were complicated by histologically confirmed placenta accreta. Placenta accreta occurred in 55 of 590 (9.3%) women with placenta previa and in 7 of 155,080 (1/22,154) without placenta previa (relative risk 2065, 95% confidence interval 944 to 4516, p < 0.0001). Among women with placenta previa, advanced maternal age (> or = 35 years) and previous cesarean delivery were independent risk factors for placenta accreta. Placenta accreta was present in 36 of 124 (29%) cases in which the placenta was implanted over the uterine scar and in 4 of 62 (6.5%) cases in which it was not (relative risk 4.5, 95% confidence interval 1.68 to 12.07). Among women with placenta previa, the risk of placenta accreta ranged from 2% in women < 35 years old with no previous cesarean deliveries to almost 39% in women with two or more previous cesarean deliveries and an anterior or central placenta previa. Placenta accreta occurs in approximately 1 of 2500 deliveries. Among women with placenta previa, the incidence is nearly 10%. In this high-risk group advanced maternal age and previous cesarean section are independent risk factors.American Journal of Obstetrics and Gynecology 07/1997; 177(1):210-4. · 3.88 Impact Factor
Article: Risk factors for placenta accreta.[show abstract] [hide abstract]
ABSTRACT: To identify risk factors associated with placenta accreta in a large cohort study. Data for this study came from the Taiwan Down Syndrome Screening Group, an ongoing project on feasibility of serum screening in an Asian population. Women who had serum screening for Down syndrome at 14-22 weeks' gestation using alpha-fetoprotein (AFP) and free beta-hCG between January 1994 and June 1997, and delivered in the same institution, were included (n = 10,672). Those who had multiple gestations (n = 200), overt diabetes (n = 11), or fetal malformations (n = 101) were excluded. If a woman was involved more than once, one randomly selected pregnancy was included in the analysis (n = 9349). Twenty-eight pregnancies were complicated by placenta accreta, diagnosed by clinical presentation (n = 26) or histologic confirmation (n = 2). Multiple logistic regression with adjustment for potentially confounding variables was used to identify independent risk factors for placenta accreta. Women who had placenta previa (odds ratio [OR] 54.2; 95% confidence interval [CI] 17.8, 165.5) and second-trimester serum levels of AFP and free beta-hCG greater than 2.5 multiples of the median (OR 8.3; 95% CI 1.8, 39.3 and OR 3.9; 95% CI 1.5, 9.9, respectively), and were 35 years and older (OR 3.2; 95% CI 1.1, 9.4) were at increased risk of having placenta accreta. Risk factors for placenta accreta include placenta previa, abnormally elevated second-trimester AFP and free beta-hCG levels, and advanced maternal age.Obstetrics and Gynecology 05/1999; 93(4):545-50. · 4.80 Impact Factor