Accuracy Of Ultrasonographic Diagnosis Of Placenta Praevia In Lagos University Teaching Hospital

Although the incidence of placenta praevia is low, accurate diagnosis may reduce hospitalization and unnecessary caesarean delivery thus reducing maternal and fetal morbidity and mortality. This study aimed to determine through a prospective study, the accuracy, sensitivity and specificity of ultrasound diagnosis of placenta praevia and the possible causes, if any, of avoidable diagnostic errors. During the study period from 1999 to 2001, 130 patients were sonographically evaluated following, either antepartum haemorrhage or incidental finding of lowlying placenta at first presentation. The patients age ranged from 19-41 years, while the gestational age ranged from 20-weeks to term. All had examination by Trans-Abdominal Sonography (TAS) with 3.5 MHz mechanical sector real-time scanner (Siemens high-resolution Sonoline SL-l ultrasound machine). Five of the patients declined Transperineal scanning (TPS). The accuracy of sonography in diagnosing placenta praevia was then compared with surgical outcome in each patient. The results showed that of the 130 patients in this study, 125 (96.2%) had examination by TPS while the remaining 5 (3.8%) declined. Out of these, 37 (28.5%) had persistent praevia till delivery, while in 93 (71.5 %), the placenta converted to a normal location. The diagnosis at delivery confirmed the sonographic diagnosis in 35/37 cases. Sonography did not predict the delivery diagnosis in 1 patient who did not have a clinically significant placenta praevia and in 2 patients who were thought not to have placenta praevia. The above 2 false negative cases were among 5 patients who declined to have TPS We conclude that combining TAS with TPS gives far more irnprovedjresults than either one used in- dividually in the diagnosis of placenta praevia.