Therapeutic outcomes of methotrexate injection in unruptured interstitial pregnancy

To examine the therapeutic outcomes of methotrexate (MTX) in the treatment of unruptured interstitial pregnancy.

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.

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/m² + 200 mg/m² 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.

Combined MTX treatment including a local injection might be an initial approach to the treatment of interstitial pregnancy.