Therapeutic outcomes of methotrexate injection in unruptured interstitial pregnancy

OBJECTIVE: To examine the therapeutic outcomes of methotrexate (MTX) in the treatment of unruptured interstitial pregnancy. METHODS: We reviewed the medical records of patients who were diagnosed with interstitial pregnancy and received MTX as first-line treatment between January 2003 and July 2014 at CHA Gangnam Medical Center. The treatment success rates and subsequent pregnancy outcomes were examined. RESULTS: Ninety-seven patients were diagnosed with interstitial pregnancy between January 2003 and July 2014. Of them, 38 initially received MTX treatment. The diagnosis was made at a median of 6(+3) weeks (5(+0) to 11(+3) weeks). Thirty patients received a systemic MTX injection, while the other 8 received a local MTX injection. Systemic treatment composed of an 8-day alternating MTX regimen, single-dose regimen, or high-dose regimen (100 mg/m(2) + 200 mg/m(2) intravenously over 12 hours). The local injection consisted of a direct MTX injection into the gestational sac with or without systemic MTX injection. Twenty-one patients (55.3%) were successfully treated with MTX. However, MTX therapy failed in 17 patients (44.7%), who required surgery. Mode of MTX treatment was the only predictive variable of MTX treatment success (P=0.039). Treatment success was seen in 7 of 8 patients (87.5%) in the local MTX group vs. 14 of 30 patients (46.7%) in the systemic MTX group. After treatment, 13 patients attempted a successive pregnancy; of them, 10 patients had a confirmed clinical pregnancy and healthy live birth. CONCLUSION: Combined MTX treatment including a local injection might be an initial approach to the treatment of interstitial pregnancy.