Factors influencing the success of conservative treatment of interstitial pregnancy

Objective To identify demographic, morphological and biochemical characteristics of interstitial pregnancies that are associated with a successful outcome of conservative treatment (expectant management or medical treatment with methotrexate). Methods Over a period of 6 years all clinically stable women with a certain ultrasound diagnosis of interstitial ectopic pregnancy were managed either expectantly (no interventions) or, medically (systemic or local methotrexate injection). The outcome of conservative treatment was compared to a number of diagnostic parameters, which were recorded at the initial visit. The treatment was classified as successful if serum human chorionic gonadotropin (hCG) level declined below 20 IU/L without the need for any additional interventions, such as the administration of methotrexate or surgery. Results A total of 42 interstitial pregnancies were diagnosed during the study period. Out of 35 women included in the final analysis 7 (20%) were managed expectantly and 28 (80%) received either local (n = 23) or systemic methotrexate (n = S). There were no significant differences in the success rates of expectant treatment and treatment with either systemic or local methotrexate. The initial median serum hCG was significantly lower in women with successful conservative management (3216 IU/L vs. 15900 IU/L; P<O.O5) but there were no other significant differences between cases with successful and failed treatment. Conclusion The measurement of serum hCG at the initial visit may be used to predict the likelihood of successful conservative treatment of interstitial pregnancy. Copyright () 2005 ISUOG. Published by John Wiley Sons, Ltd.