Prediction of Abortion Using Three- Dimensional Ultrasound Volumetry of the Gestational Sac and the Amniotic Sac in Threatened Abortion Marwan Odeh, MD, 1,2 * Ella Ophir, MD, 1,2 Vitaly Grinin, MD, 1 Rene Tendler, MD, 1 Mohamad Kais, 1 Jacob Bornstein, MD 1,2 1 Department of Obstetrics and Gynecology, Western Galilee Hospital, Nahariya, Israel 2 Bar Ilan University—Galilee Faculty of Medicine, Zefat, Israel Received 28 May 2011; accepted 7 May 2012 ABSTRACT: Purpose. To determine whether gesta- tional sac volume (GSV) or amniotic sac volume (ASV) and/or the difference between them can predict abortion in women with first-trimester threatened abortion. Methods. Ninety patients between 6 and 12 weeks of gestation presenting with vaginal bleeding were studied. Seventy-six delivered after 24 weeks of ges- tation (group A) and 14 aborted before 20 weeks of gestation (group B). All patients had a singleton via- ble pregnancy demonstrated by transvaginal ultra- sound. Gestational sac and amniotic sac volumes were measured in all the patients using three-dimen- sional transvaginal ultrasound with Virtual Organ Computer-aided Analysis software, and the gesta- tional sac volume 2 amniotic sac volume (GSV 2 ASV) was calculated. Results. The groups did not differ in terms of age, parity, number of previous abortions, or term deliv- eries. The GSV (group A: mean 32.0 6 27.7 cm 3 ; group B: 26.7 6 29.1 cm 3 ) and the ASV (group A: 21.1 6 25.5 cm 3 ; group B: 20.6 6 26.0 cm 3 ) were not statistically different, while the GSV 2 ASV was sig- nificantly smaller in group B (aborting before week 20) (group A: 10.9 6 10.9 cm 3 ; group B: 6.1 6 8.6 cm 3 ; p < 0.05). Using receiver operator curves, the area under the curve for predicting normal preg- nancy outcome of the GSV 2 ASV measurement was 0.654. When the GSV 2 ASV was 1.8 cm 3 or less, abortion was predicted with 84% sensitivity and 43% specificity. Conclusions. The measurement of the GSV and the ASV are not good predictors of abortion in patients with first-trimester vaginal bleeding, whereas the use of the GSV 2 ASV may be helpful in predicting the outcome of pregnancy. V V C 2012 Wiley Periodicals, Inc. J Clin Ultrasound 00:000–000, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/jcu.21957 Keywords: gestational sac volume; amniotic sac volume; threatened abortion; VOCAL M iscarriage occurs in about 10–15% of clini- cally recognized conceptions. 1 Several sono- graphic (US) parameters are used to predict a normal pregnancy outcome in the first trimester. These include the size and location of the gesta- tional sac, 2 the growth rate of the gestational sac, 3 the gestational sac size in relation to the presence or absence of fetal pole and yolk sac, 4–7 the size and shape of the yolk sac, 8,9 the fetal heart rate, 10,11 and the relationship between the gestational sac mean size and the crown rump length (CRL). 12–15 Threatened abortion is a risk factor for poor pregnancy outcome, 16 including spontaneous pregnancy loss before 24 weeks of gestation, pree- clampsia, preterm delivery, placental abruption, cesarean delivery, and intrauterine growth restriction. 16 We have reported that gestational sac volume (GSV) is smaller in cases of missed abortion beginning as early as 7 weeks of gestation. 17 However, to the best of our knowledge, three- dimensional (3D) measurements of the GSV or the amniotic sac volume (ASV) have not been uti- Correspondence to: M. Odeh ' 2012 Wiley Periodicals, Inc. VOL. 00, NO. 0, MONTH 2012 1