Serial endovaginal sonography of ectopic pregnancies treated with methotrexate

Methotrexate therapy is a newly established treatment modality for ectopic pregnancy. We performed this study to determine the time frame for resolution of the sonographically identifiable mass during such therapy and to determine the role of sonography in the management of these patients. Eighteen patients treated with methotrexate for laparoscopically proven ectopic pregnancy consented to long-term follow-up with endovaginal sonography. These 18 patients constitute the study group. The time required for sonographic resolution of the mass was variable, although poor patient compliance with sonographic follow-up affected the conclusions regarding resolution time. One hundred eight days was the longest period accurately known for resolution of a mass. In seven patients, the mass persisted after a negative hCG titer. Enlargement of the adnexal mass during therapy did not necessarily predict treatment failure, as only two of ten such patients required surgery for rupture. Serial sonography did not alter the management of most patients and appears not to be warranted on a routine basis. Follow-up sonography was most useful when complications were suspected. All patients considered for methotrexate therapy should first have an endovaginal sonogram, as cardiac activity remains a relative contraindication to this treatment. We have determined that the mass of an ectopic pregnancy may remain after the hCG is negative. Therefore, a persistent mass should not be interpreted as treatment failure.