The impact of pre-evacuation ultrasound examination in histologically confirmed hydatidiform mole in missed abortion

BACKGROUND: Early detecting hydatidiform mole in missed abortion is challenge. In this retrospective observational study, we analysed the sensitivity of detecting hydatidiform mole by pre-evacuation ultrasound examination or naked eye after surgical uterine evacuation in missed abortion. METHODS: Data on 577 cases with histologically confirmed hydatidiform mole were collected over a 10-year period and analysed. Data included serum β-hCG level before surgical evacuation, the ultrasound examination findings, histology findings and naked eye findings. In addition, serum β-hCG level on 2398 cases without hydatidiform mole was also collected. RESULTS: The median maternal age was 29 (range, 17–53) years and the range of gestational age was 6 to 12 weeks. The sensitivity of detecting hydatidiform mole by ultrasound examination or by naked eye was 25% or 60% respectively. This sensitivity was not increased by the combination of ultrasound and naked eye. There was no difference in the sensitivity of detecting subtypes of hydatidiform mole. The higher β-hCG level was seen in cases with hydatidiform mole, compared to cases without hydatidiform mole. However, there was a lot of overlap in the distributions of β-hCG between the two groups. CONCLUSIONS: In this study, we found lower sensitivity of detecting hydatidiform mole by ultrasound in missed abortion. β-hCG level was higher in hydatidiform mole than in non- hydatidiform mole in missed abortion. Although higher sensitivity of detecting hydatidiform mole is seen by naked eye (60%), in order to minimise missed opportunity of detecting hydatidiform mole, our study suggests that routine histopathological examination is necessary in missed abortion.