Table of Contents
ISRN Obstetrics and Gynecology
Volume 2013, Article ID 269425, 4 pages
Clinical Study

The Importance of Gestational Sac Size of Ectopic Pregnancy in Response to Single-Dose Methotrexate

1Department of Obstetrics and Gynecology, Mahdiyeh Hospital, Shahid Beheshti University of Medical Sciences, No. 16, Fadaieaneslam Street, Shoush Avenue, Tehran 1185817311, Iran
2Department of Obstetrics and Gynecology, Tehran University of Medical Sciences, Tehran 1417614411, Iran

Received 17 December 2012; Accepted 5 February 2013

Academic Editors: L. G. Bahamondes, J. A. Cesar, and I. Diez-Itza

Copyright © 2013 Parichehr Kimiaei et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This retrospective cohort study was designed in a selective group of 185 patients diagnosed with and treated for ectopic pregnancy. Intramuscular administration of a single dose of methotrexate (50 mg/m2) was performed to measure predictors of failure or resistance to treatment necessitating surgical intervention. During the time of treatment with a single dose of MTX, 20 patients (10.8%) failed to response, in which 6 of 20 (30%) indicated side effects to MTX and rupture of the ectopic pregnancy. Remaining cases ( ) showed resistance to the drug; the level of β-hCG did not fall at least 15% during 7 days after treatment and necessitated laparotomy. In backward-step analysis by multiple logistic regressions of various types of predictor factors, size of gestational sac (coefficient = 1.91, OR = 6.78, 95% confidence interval = 3.18–8.22) and baseline level β-hCG (coefficient = 1.60, OR = 5.0, 95% confidence interval = 4.26–6.72) had significant correlation with leading EP patients failing to response to MTX. This study suggests that further investigation for finding relative contraindications of MTX treatment in EP women should be considered on the gestational sac size because other variables are in the causal pathway of this variable.