Successful treatment of an advanced interstitial pregnancy by sequential systemic and local administration of methotrexate.

A patient is presented with an advanced interstitial pregnancy, diagnosed by transvaginal ultrasound and confirmed by laparoscopy. Amenorrhoea at the time of diagnosis was 57 days. Methotrexate was given systemically (4 x 50 mg i.m.). Because of persisting viability of the fetus, systemic methotrexate treatment was followed by local instillation of methotrexate into the gestational sac (50 mg). Follow-up revealed rapid human chorionic gonadotrophin regression but slow regression of fetal remnants.