ImagingSonographic detection of placenta accreta in the second and third trimesters of pregnancy
Section snippets
Methods
Prospectively, all patients who were seen for a fetal ultrasound examination between March 1990 (when an electronic database was adopted) and August 2002 were asked whether they had ever had a cesarean delivery. If the answer was affirmative, a sonographic examination was performed over the area of the presumed uterine scar to determine whether there were any sonographic signs of placenta accreta. This study was exempted from review by the William Beaumont Institutional Review Board.
Scans were
Results
Over the 12 years of the study period, 163,855 obstetrics examinations were performed in our unit. Of these, 2002 patients had dual risk factors of a history of a previous cesarean delivery, along with the ultrasound finding of either a placenta previa or low anterior placenta (lower edge <2 cm from the internal os). In 33 of these 2002 cases, ultrasound findings that were suspicious for a placenta accreta were noted on at least 1 scan (1.6%). These 33 cases form the basis of our study on the
Comment
The findings of this study supplement our earlier report that showed an association of a low gestational sac that was seen on first trimester scans for patients with placenta accreta.7
Discussion
We found that obliteration of the clear space can develop over the course of pregnancy but that the clear space alone is not a good diagnostic sign for placenta accreta. Visualization of placental lacunae was the most reliable diagnostic sign. In addition, we found lacunae as early as 15 weeks of gestation in most patients who were examined then. This is a noteworthy finding because mid second trimester is the time at which most patients have their “screening” ultrasound examination. Only 3 of
Supplementary Files
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