TY - JOUR T1 - 178 The accuracy of ultrasound in diagnosing first trimester molar pregnancy JF - International Journal of Gynecologic Cancer JO - Int J Gynecol Cancer SP - A77 LP - A78 DO - 10.1136/ijgc-2020-IGCS.155 VL - 30 IS - Suppl 3 AU - R Medalla AU - L David-Bustamante Y1 - 2020/11/01 UR - http://ijgc.bmj.com/content/30/Suppl_3/A77.abstract N2 - Molar pregnancies are associated with more medical complications as gestational age increases and thus, early diagnosis is of great importance to its management. Histologic examination remains to be the gold standard for its diagnosis but ultrasound has been the preferred imaging modality for its initial screening.The Philippine General Hospital is a recognized Trophoblastic Disease Center thus, evaluation of the accuracy of ultrasound is important for early screening and management. The aim of this study is to determine the accuracy of ultrasound in diagnosing first trimester molar pregnancy. A cross sectional study was performed involving 172 cases of first trimester molar and non-molar pregnancies. Thirty-six molar pregnancies were identified on ultrasound, and 5 cases had histopathologic findings of non-molar pregnancies. Of the 136 non-molar pregnancies, 3 cases had histopathologic findings of hydatidiform mole. Ultrasound findings of hydatidiform mole showed a heterogeneous mass with multiple cystic spaces and low level echo fluid. Overall, ultrasound has a sensitivity of 91.2% and specificity of 96.4%. The positive predictive value is 11.2% and negative predictive value is 97.8%. This shows that in PGH, first trimester ultrasound remains to be an excellent initial diagnostic modality for molar pregnancies.View this table:Abstract 178 Table 1 False negative molar pregnancies by ultrasoundAbstract 178 Figure 1 Sonographic pictures of histopathologically confirmed molar pregnancies. A and B. Hetergoneous mass with multiple cystic spaces within. C. Absence of vascularity on doppler studies ER -