When is seeing believing? The use of color Doppler ultrasound to diagnose placenta accreta in the first trimester of pregnancy

Pathophysiology of placenta creta: the role of decidua and extravillous trophoblast

Placenta creta is associated with massive postpartum hemorrhage and commonly leads to emergency hysterectomy. While the exact pathogenesis of placenta creta is unknown, proposed hypotheses include a primary deficiency of decidua, abnormal maternal vascular remodeling, excessive trophoblastic invasion, or a combination thereof. To assess these changes in placenta creta, we retrospectively reviewed 49 cases of gravid hysterectomy, 38 with and 11 without the diagnosis of creta, gathered clinical data, and evaluated histopathology of extravillous trophoblast. Specifically, we evaluated maternal vessels for remodeling by endovascular trophoblast, as well as the morphology and depth of invasion of interstitial trophoblast at the implantation site. Compared to controls, cases with creta had decreased proportion of remodeled vessels, with many vessels displaying partial physiologic change. Cases with creta also demonstrated vascular remodeling deeper in the myometrium; however, vascular remodeling of large outer myometrial vessels was only demonstrated in increta and percreta cases, and was absent in both non-creta and accreta. As previously reported, interstitial trophoblast invaded the uterine wall to a significantly greater depth in placenta creta; however, there was no significant difference between creta subtypes. Finally, Ki-67 staining was rarely observed in extravillous trophoblast, except in the trophoblast columns of first trimester creta cases. We, therefore, conclude that the pathogenesis of placenta creta is multi-dimensional, involving increased, but incomplete trophoblast invasion in a background of absent decidua. We further propose that placenta increta and percreta are not due to a further invasion of extravillous trophoblast in the uterine wall, rather they likely arise secondary to dehiscence of a scar, leading to the presence of chorionic villi deep within the uterine wall, and thus give extravillous trophoblast greater access to the deep myometrium.

Differential expression of growth-, angiogenesis- and invasion-related factors in the development of placenta accreta

Placenta accreta is the major cause of maternal death complicated by massive peripartum hemorrhage. Its development is traditionally considered to be related to a decidual defect caused by previous cesarean deliveries or uterine curettages. Usually, placental villi firmly adhere to the superficial myometrium and deeply invade, or even penetrate, the uterine wall. Abnormal uteroplacental neovascularization is another characteristic. Therefore, we hypothesized that placenta accreta develops as a result of abnormal expressions of growth-, angiogenesis- and invasion-related factors in trophoblast populations. We have found, in pregnancies complicated by placenta accreta: upregulated epidermal growth factor receptor and downregulated c-erbB-2 oncoprotein in syncytiotrophoblasts; downregulated vasculoendothelial growth factor receptor-2 expression in syncytiotrophoblasts and increased vasculoendothelial growth factor in placental lysates; and downregulated Tie-2 expression in syncytiotrophoblasts and enhanced angiopoietin-2 level in placental lysates. However, matrix metalloproteinase expression was not upregulated, so the association of these invasion-related molecules with placenta accreta is less likely. Taken together, these findings imply that complex factors, either alone or in combination, might be responsible for the development of placenta accreta. Further studies are needed to understand the signaling pathways and possible genetic events.

Experience with Conservative Strategy of Uterine Artery Embolization in the Treatment of Placenta Percreta in the first Trimester of Pregnancy

OBJECTIVE

There is little prospective experience in the conservative treatment of placenta percreta during the first trimester in order to preserve uterine fertility. We describe herein our experience with uterine artery embolization (UAE) in the management of placenta percreta at 9 weeks of gestation.

CASE REPORT

A 36-year-old woman, gravida 3, para 1, was referred for ultrasonographic evaluation because of suspected molar pregnancy due to persistent vaginal spotting at 9 weeks of gestation. A Grade 3+ lacunar flow pattern with multiple bizarre and large irregular sonolucent spaces were observed. Color Doppler imaging revealed extensive turbulent lacunar blood flow perfusing throughout the whole surrounding uteroplacental tissues and fetus. The patient was informed of the situation and she had a strong desire to avoid surgery. Conservative management with bilateral UAE was performed using polyvinyl alcohol particles to promote involution and shedding of the abnormally adherent placenta. However, an unsatisfactory vessel-occluding effect caused by extensive collateral supply was still detected after repeated UAE. We, therefore, performed hysterectomy, and the patient had an uneventful postoperative course.

CONCLUSION

The efficacy and complications of UAE as a therapeutic modality for the conservative management of invasive placentation in the first trimester of pregnancy are not clear, as this is the first report of its kind. However, although UAE had failed in this case, it may still be a useful procedure as a prophylactic measure before surgical intervention, and hysterectomy can also be performed for better control of operative hemorrhage.

Expression of epidermal growth factor receptor and c-erbB-2 oncoprotein in trophoblast populations of placenta accreta

OBJECTIVE

The purpose of this study was to investigate the expression of epidermal growth factor receptor and c-erbB-2 oncoprotein in trophoblast populations of placenta accreta.

STUDY DESIGN

Paraffin sections of 43 placental specimens with (cases) and 43 without (controls) placenta accreta were studied immunohistochemically for epidermal growth factor receptor and c-erbB-2 expression in the syncytiotrophoblast, villous cytotrophoblast, and extravillous cytotrophoblast. Epidermal growth factor receptor and c-erbB-2 protein levels were also performed by Western blot analysis. Controls were matched for gestational age in this case-control study.

RESULTS

The percentage of strong/intermediate immunoreactivity of epidermal growth factor receptor in the syncytiotrophoblast was significantly higher in cases (98%) than controls (79%; odds ratio,11.1; 95% CI, 1.3-92.0; P = .03), although strong/intermediate immunoreactivity of c-erbB-2 in the syncytiotrophoblast was significantly lower in cases (35%) than controls (81%; odds ratio, 0.1; 95% CI, 0.1-0.3; P < .001). Epidermal growth factor receptor and c-erbB-2 expression in the villous and extravillous cytotrophoblastic cells were not significantly different between controls and cases ( P > .05). Most immunoreactive bands on Western blots were consistent with the trends of immunohistochemical findings.

CONCLUSION

The development of placenta accreta is related closely to the differential expression of epidermal growth factor receptor and c-erbB-2 in the syncytiotrophoblast.