Contrast-Enhanced Ultrasound Evaluation of Mifepristone for Treatment of Low-Risk Cesarean Scar Pregnancy

Abstract

Purpose. The effect of mifepristone for treatment of low-risk cesarean scar pregnancy (CSP) was monitored by contrast-enhanced ultrasound (CEUS). Methods. Data were collected from 23 CSP patients with a 10-point risk score <5 (low-risk CSP) and from 23 intrauterine pregnancy (IUP) patients with a scar from a previous cesarean delivery. All patients were prescribed 75 mg mifepristone daily for 2 days and underwent transvaginal CEUS before and after administration of mifepristone. On the third day, uterine curettage was performed after transvaginal CEUS. Arrival time (AT), peak intensity (PI), and area under the curve (AUC) around the gestational sac were monitored by CEUS before and after application of mifepristone, and the rate of effective treatment was compared between the two patient groups. Results. No patients experienced side effects from either the CEUS procedure or the mifepristone treatment. Changes in AT, PI, and AUC index from before vs. after mifepristone treatment did not differ significantly between the two groups (all $p$ values >0.05). There was also no significant difference in the rate of effective treatment between the two groups (95.65% in the CSP group vs. 100% in the IUP group; $p>0.05$ ). Conclusions. Based on monitoring by CEUS, the effect of mifepristone in low-risk CSP was comparable to that in IUP.