A thin decidua can also be a contributing factor to such trophoblastic invasion. Some studies suggest that the rate of incidence is higher when the fetus is female. Other risk factors include low-lying placenta, anterior placenta, congenital or acquired uterine defects (such as uterine septa), leiomyoma, ectopic implantation of placenta (including cornual pregnancy).Pregnant women above 35 years of age who have had a caesarian section and now have a placenta previa overlying the uterine scar have a 40% chance of placenta accreta. Pathogenesis
The placenta forms an abnormally firm and deep attachment to the uterine wall. There is absence of the decidua basalis and incomplete development of the Nitabuchs layer. There are three forms of placenta accreta, distinguishable by the depth of penetration. Diagnosis
When the antepartum diagnosis of placenta accreta is made, it is usually based on ultrasound findings in the second or third trimester. Sonographic findings that may be suggestive of placenta accreta include:

Loss of normal hypoechoic retroplacental zone
Multiple vascular lacunae (irregular vascular spaces) within placenta, giving "Swiss cheese" appearance
Blood vessels or placental tissue bridging uterine-placental margin, myometrial-bladder interface, or crossing the uterine serosa
Retroplacental myometrial thickness of <1 mm
Numerous coherent vessels visualized with 3-dimensional power Doppler in basal viewUnfortunately, the diagnosis is not easy and is affected by a significant interobserver variability. In doubtful cases it is possible to perform a nuclear magnetic resonance (MRI) of the pelvis, which has a very good sensitivity and specificity for this disorder.
Esterified estrogens/methyltestosterone (EEs/MT), sold under brand names such as Covaryx, Eemt, Essian, Estratest, Menogen, and Syntest, is a hormonal preparation that combines esterified estrogens (EEs) with methyltestosterone (MT) in one tablet and is used in menopausal hormone therapy. Medical uses
EEs/MT is used to treat menopausal women who suffer from hot flashes, but do not get relief from estrogen-only therapy. Available forms
EEs/MT is sold in tablet form, with either 1.25 mg EEs/2.5 mg MT or 0.625 mg EEs/1.25 mg MT available. Pharmacology
The product is a combination of esterified estrogens, an estrogen, and low-dose methyltestosterone, an androgen/anabolic steroid, in a single tablet. History
EEs/MT was first marketed in the United States in 1965 by Reid-Provident Laboratories, which as 100% of Reid-Rowell, Inc. stock was acquired by the Belgian pharmaceutical company Solvay in 1986. There has been some controversy surrounding the drug in recent years as to its status with the U.S. Food and Drug Administration. Solvay sponsored a clinical trial of EEs/MT in the United States to determine whether the product is superior to treatment with esterified estrogens tablets. EEs/MT was supplied by Solvay. In March 2009 Solvay announced that, based on a variety of business factors, it would discontinue supplying Estratest and Estratest HS tablets, and would stop accepting orders for the product on March 31, 2009. See also
Conjugated estrogens/methyltestosterone
List of combined sex-hormonal preparations

References
External links
The products web site